[ { "id": "ptau217-lilly-msd-palmqvist2020-autopsy", "assay_name": "Eli Lilly MSD plasma p-tau217 (research assay)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Palmqvist et al. 2020, JAMA", "cohort": "Arizona neuropathology cohort (Banner Sun Health; cohort 1: 34 AD, 47 non-AD)", "n_participants": 81, "population": "mixed", "comparator": "autopsy", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.89, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2020, "publication": "JAMA 324(8):772-781", "url": "https://doi.org/10.1001/jama.2020.12134", "doi": "10.1001/jama.2020.12134", "pubmed_id": "32722745", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Antemortem plasma p-tau217 vs neuropathologically defined AD; AUC 0.89 (95% CI 0.81-0.97). Plasma p-tau181 and NfL AUC range 0.50-0.72 in same cohort. Mean age 83.5 y. Sensitivity/specificity not reported in abstract.", "evidence_strength": "moderate (small autopsy cohort, selected)" }, { "id": "ptau217-lilly-msd-palmqvist2020-biofinder2", "assay_name": "Eli Lilly MSD plasma p-tau217 (research assay)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Palmqvist et al. 2020, JAMA", "cohort": "Swedish BioFINDER-2 (cohort 2: 301 CU, 178 MCI, 121 AD dementia, 99 other neurodegenerative)", "n_participants": 699, "population": "memory-clinic", "comparator": "clinical-diagnosis", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.96, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2020, "publication": "JAMA 324(8):772-781", "url": "https://doi.org/10.1001/jama.2020.12134", "doi": "10.1001/jama.2020.12134", "pubmed_id": "32722745", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Clinical AD dementia vs other neurodegenerative diseases: AUC 0.96 (95% CI 0.93-0.98). Not significantly different from CSF p-tau217, CSF p-tau181 or tau-PET (AUC 0.90-0.99). Abnormal vs normal tau-PET: AUC 0.93 (0.91-0.96). This is the origin of the 'approaches PET/CSF accuracy' claim; note the comparison is dementia-stage AD vs other neurodegenerative disease in a research cohort, not amyloid-PET status in an unselected population.", "evidence_strength": "moderate-high (large research cohort; selected participants)" }, { "id": "ptau217-lilly-msd-mielke2022-mcsa", "assay_name": "Eli Lilly MSD plasma p-tau217 (research assay)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Mielke et al. 2022, Nature Medicine", "cohort": "Mayo Clinic Study of Aging (population-based, age 30-98)", "n_participants": 1329, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2022, "publication": "Nature Medicine 28:1398-1405", "url": "https://doi.org/10.1038/s41591-022-01822-2", "doi": "10.1038/s41591-022-01822-2", "pubmed_id": "35618838", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "KEY COUNTER-EVIDENCE to headline accuracy: in an unselected community sample, continuous unadjusted plasma p-tau181 and p-tau217 predicted abnormal amyloid-PET with AUROC only 0.81-0.86 (range given jointly for both analytes in abstract; AUC field left null because the abstract does not give a p-tau217-specific point value). Tau-PET temporal ROI AUROC <0.70. Chronic kidney disease raised p-tau levels by an amount similar to the amyloid-positive vs -negative difference.", "evidence_strength": "high (population-based)" }, { "id": "ptau181-lilly-msd-mielke2022-mcsa", "assay_name": "Eli Lilly MSD plasma p-tau181 (research assay)", "analyte": "p-tau181", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Mielke et al. 2022, Nature Medicine", "cohort": "Mayo Clinic Study of Aging (population-based, age 30-98)", "n_participants": 1329, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2022, "publication": "Nature Medicine 28:1398-1405", "url": "https://doi.org/10.1038/s41591-022-01822-2", "doi": "10.1038/s41591-022-01822-2", "pubmed_id": "35618838", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract reports AUROC 0.81-0.86 jointly for p-tau181 and p-tau217 vs abnormal amyloid-PET in a community sample; analyte-specific value not in abstract (null). Comorbidities (CKD) confound levels.", "evidence_strength": "high (population-based)" }, { "id": "ptau217-washu-ms-janelidze2023-h2h", "assay_name": "Washington University mass-spectrometry plasma p-tau217", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Janelidze et al. 2023, Brain (head-to-head of 10 plasma p-tau assays)", "cohort": "BioFINDER-1 MCI patients (n=135; 71 Aβ-positive by CSF Aβ42/40; mean age 72.4)", "n_participants": 135, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.947, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Brain 146(4):1592-1601", "url": "https://doi.org/10.1093/brain/awac333", "doi": "10.1093/brain/awac333", "pubmed_id": "36087307", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Detection of abnormal Aβ status (CSF Aβ42/40 reference): AUC 0.947, significantly better than all 9 other assays (Pdiff<0.015). AUC for progression to AD dementia 0.932. Plasma-CSF correlation R=0.891.", "evidence_strength": "moderate (single small MCI cohort; head-to-head design is the strength)" }, { "id": "ptau217-lilly-msd-janelidze2023-h2h", "assay_name": "Eli Lilly MSD plasma p-tau217", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Janelidze et al. 2023, Brain (head-to-head of 10 plasma p-tau assays)", "cohort": "BioFINDER-1 MCI patients (n=135; 71 Aβ-positive by CSF Aβ42/40; mean age 72.4)", "n_participants": 135, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.886, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Brain 146(4):1592-1601", "url": "https://doi.org/10.1093/brain/awac333", "doi": "10.1093/brain/awac333", "pubmed_id": "36087307", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract gives AUC range 0.886-0.889 across the two outcomes (abnormal Aβ status; progression to AD dementia); lower bound recorded. Best of the immunoassays; not significantly different from Janssen p-tau217, ADx p-tau181, WashU p-tau181 (AUC 0.835-0.872).", "evidence_strength": "moderate (single small MCI cohort; head-to-head design is the strength)" }, { "id": "ptau217-janssen-simoa-janelidze2023-h2h", "assay_name": "Janssen Simoa plasma p-tau217", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Janelidze et al. 2023, Brain (head-to-head of 10 plasma p-tau assays)", "cohort": "BioFINDER-1 MCI patients (n=135; 71 Aβ-positive by CSF Aβ42/40; mean age 72.4)", "n_participants": 135, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Brain 146(4):1592-1601", "url": "https://doi.org/10.1093/brain/awac333", "doi": "10.1093/brain/awac333", "pubmed_id": "36087307", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract reports only that Janssen p-tau217 AUC fell in the range 0.835-0.872 (grouped with ADx p-tau181 and WashU p-tau181) and was not significantly different from Lilly p-tau217; assay-specific AUC not in abstract (null).", "evidence_strength": "moderate (single small MCI cohort; head-to-head design is the strength)" }, { "id": "ptau181-lilly-msd-janelidze2023-h2h", "assay_name": "Eli Lilly MSD plasma p-tau181", "analyte": "p-tau181", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Janelidze et al. 2023, Brain (head-to-head of 10 plasma p-tau assays)", "cohort": "BioFINDER-1 MCI patients (n=135; 71 Aβ-positive by CSF Aβ42/40; mean age 72.4)", "n_participants": 135, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Brain 146(4):1592-1601", "url": "https://doi.org/10.1093/brain/awac333", "doi": "10.1093/brain/awac333", "pubmed_id": "36087307", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract groups Lilly p-tau181 with p-tau231 UGOT, p-tau181 UGOT, p-tau181 Fujirebio Lumipulse and p-tau181 MSD Splex in AUC range 0.642-0.813, significantly lower than Lilly p-tau217 (Pdiff<=0.029). Assay-specific AUC not in abstract (null).", "evidence_strength": "moderate (single small MCI cohort; head-to-head design is the strength)" }, { "id": "ptau181-fujirebio-lumipulse-janelidze2023-h2h", "assay_name": "Fujirebio Lumipulse plasma p-tau181", "analyte": "p-tau181", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Janelidze et al. 2023, Brain (head-to-head of 10 plasma p-tau assays)", "cohort": "BioFINDER-1 MCI patients (n=135; 71 Aβ-positive by CSF Aβ42/40; mean age 72.4)", "n_participants": 135, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Brain 146(4):1592-1601", "url": "https://doi.org/10.1093/brain/awac333", "doi": "10.1093/brain/awac333", "pubmed_id": "36087307", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract groups Fujirebio Lumipulse p-tau181 in AUC range 0.642-0.813, significantly lower than Lilly p-tau217. Assay-specific AUC not in abstract (null).", "evidence_strength": "moderate (single small MCI cohort; head-to-head design is the strength)" }, { "id": "ptau181-ugot-simoa-janelidze2023-h2h", "assay_name": "University of Gothenburg Simoa plasma p-tau181", "analyte": "p-tau181", "platform": "Simoa", "sample_type": "plasma", "study_name": "Janelidze et al. 2023, Brain (head-to-head of 10 plasma p-tau assays)", "cohort": "BioFINDER-1 MCI patients (n=135; 71 Aβ-positive by CSF Aβ42/40; mean age 72.4)", "n_participants": 135, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Brain 146(4):1592-1601", "url": "https://doi.org/10.1093/brain/awac333", "doi": "10.1093/brain/awac333", "pubmed_id": "36087307", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract groups UGOT Simoa p-tau181 in AUC range 0.642-0.813. Assay-specific AUC not in abstract (null).", "evidence_strength": "moderate (single small MCI cohort; head-to-head design is the strength)" }, { "id": "pctptau217-washu-ms-barthelemy2024", "assay_name": "Washington University / C2N mass-spectrometry plasma %p-tau217 (p-tau217/np-tau217 ratio)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Barthélemy et al. 2024, Nature Medicine", "cohort": "BioFINDER-2 (n=1,422) and Knight ADRC (n=337); cognitively impaired subcohorts BioFINDER-2 n=720, Knight ADRC n=50", "n_participants": 1759, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.95, "ppv_pct": 89, "npv_pct": 89, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Nature Medicine 30:1085-1095", "url": "https://doi.org/10.1038/s41591-024-02869-z", "doi": "10.1038/s41591-024-02869-z", "pubmed_id": "38382645", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC for amyloid-PET status reported as 'between 0.95 and 0.97' (lower bound recorded); tau-PET AUC 0.95-0.98. In cognitively impaired subcohorts accuracy/PPV/NPV 89-90% for amyloid-PET (lower bound recorded), 87-88% for tau-PET; 95% with a two-cutoff approach (intermediate zone excluded). Judged clinically equivalent to FDA-approved CSF Aβ42/40 and p-tau181/Aβ42 immunoassays. Research cohorts, not primary care. %p-tau217 is the basis of C2N PrecivityAD2 (LDT).", "evidence_strength": "high (two cohorts, PET reference), but research settings" }, { "id": "aps2-c2n-palmqvist2024-primary-batch", "assay_name": "C2N PrecivityAD2 (APS2: mass-spec %p-tau217 + Aβ42/40)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Palmqvist et al. 2024, JAMA", "cohort": "Swedish primary care, single-batch analysis (n=307)", "n_participants": 307, "population": "primary-care", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.97, "ppv_pct": 91, "npv_pct": 92, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "JAMA 332(15):1245-1257", "url": "https://doi.org/10.1001/jama.2024.13855", "doi": "10.1001/jama.2024.13855", "pubmed_id": "39068545", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.97 (95% CI 0.95-0.99), PPV 91% (87-96), NPV 92% (87-96). Reference standard = AD pathology defined by abnormal CSF Aβ42/40 and p-tau217 (not amyloid-PET). Predefined cutoffs from an independent cohort. Overall diagnostic accuracy APS2 90% (88-92) vs %p-tau217 alone 90% (88-91): adding Aβ42/40 did not improve accuracy. Prevalence of AD pathology 50% in both settings; PPV/NPV will differ at other prevalences.", "evidence_strength": "high (prospective, predefined cutoffs, real-world primary care)" }, { "id": "aps2-c2n-palmqvist2024-secondary-batch", "assay_name": "C2N PrecivityAD2 (APS2: mass-spec %p-tau217 + Aβ42/40)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Palmqvist et al. 2024, JAMA", "cohort": "Swedish secondary care (memory clinic), single-batch analysis (n=300)", "n_participants": 300, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.96, "ppv_pct": 88, "npv_pct": 87, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "JAMA 332(15):1245-1257", "url": "https://doi.org/10.1001/jama.2024.13855", "doi": "10.1001/jama.2024.13855", "pubmed_id": "39068545", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.96 (0.94-0.98), PPV 88% (83-93), NPV 87% (82-93). Reference standard = AD pathology defined by abnormal CSF Aβ42/40 and p-tau217 (not amyloid-PET). Predefined cutoffs from an independent cohort. Overall diagnostic accuracy APS2 90% (88-92) vs %p-tau217 alone 90% (88-91): adding Aβ42/40 did not improve accuracy. Prevalence of AD pathology 50% in both settings; PPV/NPV will differ at other prevalences.", "evidence_strength": "high (prospective, predefined cutoffs, real-world primary care)" }, { "id": "aps2-c2n-palmqvist2024-primary-prospective", "assay_name": "C2N PrecivityAD2 (APS2: mass-spec %p-tau217 + Aβ42/40)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Palmqvist et al. 2024, JAMA", "cohort": "Swedish primary care, prospective biweekly analysis (n=208)", "n_participants": 208, "population": "primary-care", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.96, "ppv_pct": 88, "npv_pct": 90, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "JAMA 332(15):1245-1257", "url": "https://doi.org/10.1001/jama.2024.13855", "doi": "10.1001/jama.2024.13855", "pubmed_id": "39068545", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.96 (0.94-0.98), PPV 88% (81-94), NPV 90% (84-96). Primary care physicians' clinical accuracy for AD was 61% (53-69) vs 91% (86-96) with APS2. Reference standard = AD pathology defined by abnormal CSF Aβ42/40 and p-tau217 (not amyloid-PET). Predefined cutoffs from an independent cohort. Overall diagnostic accuracy APS2 90% (88-92) vs %p-tau217 alone 90% (88-91): adding Aβ42/40 did not improve accuracy. Prevalence of AD pathology 50% in both settings; PPV/NPV will differ at other prevalences.", "evidence_strength": "high (prospective, predefined cutoffs, real-world primary care)" }, { "id": "aps2-c2n-palmqvist2024-secondary-prospective", "assay_name": "C2N PrecivityAD2 (APS2: mass-spec %p-tau217 + Aβ42/40)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Palmqvist et al. 2024, JAMA", "cohort": "Swedish secondary care (memory clinic), prospective biweekly analysis (n=398)", "n_participants": 398, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.97, "ppv_pct": 91, "npv_pct": 91, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "JAMA 332(15):1245-1257", "url": "https://doi.org/10.1001/jama.2024.13855", "doi": "10.1001/jama.2024.13855", "pubmed_id": "39068545", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.97 (0.95-0.98), PPV 91% (87-95), NPV 91% (87-95). Dementia specialists' clinical accuracy 73% (68-79) vs 91% (88-95) with APS2. Reference standard = AD pathology defined by abnormal CSF Aβ42/40 and p-tau217 (not amyloid-PET). Predefined cutoffs from an independent cohort. Overall diagnostic accuracy APS2 90% (88-92) vs %p-tau217 alone 90% (88-91): adding Aβ42/40 did not improve accuracy. Prevalence of AD pathology 50% in both settings; PPV/NPV will differ at other prevalences.", "evidence_strength": "high (prospective, predefined cutoffs, real-world primary care)" }, { "id": "ptau217-alzpath-simoa-ashton2024", "assay_name": "ALZpath pTau217 (Simoa HD-X immunoassay)", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Ashton et al. 2024, JAMA Neurology", "cohort": "TRIAD (Montreal), WRAP (Wisconsin), SPIN (Barcelona); n=786, mean age 66.3", "n_participants": 786, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.92, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "JAMA Neurology 81(3):255-263", "url": "https://doi.org/10.1001/jamaneurol.2023.5319", "doi": "10.1001/jamaneurol.2023.5319", "pubmed_id": "38252443", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC for elevated Aβ reported as range 0.92-0.96 across 3 cohorts (95% CI 0.89-0.99); lower bound recorded. Tau pathology AUC 0.93-0.97. Reference standard was PET or CSF depending on cohort. 3-range reference (intermediate zone) reduced confirmatory testing by ~80%. Research cohorts, mean age 66; not primary care.", "evidence_strength": "moderate-high (3 cohorts, but research volunteers)" }, { "id": "pctptau217-washu-ms-warmenhoven2025-h2h", "assay_name": "Washington University / C2N mass-spec plasma %p-tau217", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Warmenhoven et al. 2025, Brain (head-to-head of key plasma p-tau217 tests)", "cohort": "BioFINDER-2 (n=998, CU and CI, mean age 68.5); replicated in Knight ADRC/WashU (n=219)", "n_participants": 998, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 91, "specificity_pct": 94, "auc": 0.96, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Brain 148(2):416-431", "url": "https://doi.org/10.1093/brain/awae346", "doi": "10.1093/brain/awae346", "pubmed_id": "39468767", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Highest performer: accuracy 0.93, sensitivity 91%, specificity 94% for Aβ-PET status. AUC recorded as upper bound of the 0.91-0.96 range for all p-tau217 tests since abstract states %p-tau217 had significantly higher AUC than all immunoassays (Pdiff<0.007); exact point AUC is in full text, not abstract. Authors: MS %p-tau217 may serve as stand-alone confirmatory test; immunoassays better suited as triage tests.", "evidence_strength": "high (large head-to-head with PET reference, external replication)" }, { "id": "ptau217-lilly-msd-warmenhoven2025-h2h", "assay_name": "Eli Lilly MSD plasma p-tau217", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Warmenhoven et al. 2025, Brain (head-to-head of key plasma p-tau217 tests)", "cohort": "BioFINDER-2 (n=998, CU and CI, mean age 68.5); replicated in Knight ADRC/WashU (n=219)", "n_participants": 998, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Brain 148(2):416-431", "url": "https://doi.org/10.1093/brain/awae346", "doi": "10.1093/brain/awae346", "pubmed_id": "39468767", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Immunoassays as a group: accuracy 0.83-0.88, sensitivity 84-87%, specificity 85-89% for Aβ-PET (assay-specific values not in abstract; null). Lilly and ALZpath had higher AUC than Janssen for Aβ-PET (Pdiff<0.006); Lilly outperformed ALZpath for tau-PET (Pdiff=0.025). All plasma p-tau217 tests AUC range 0.91-0.96.", "evidence_strength": "high (large head-to-head with PET reference, external replication)" }, { "id": "ptau217-alzpath-simoa-warmenhoven2025-h2h", "assay_name": "ALZpath pTau217 (Simoa)", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Warmenhoven et al. 2025, Brain (head-to-head of key plasma p-tau217 tests)", "cohort": "BioFINDER-2 (n=998, CU and CI, mean age 68.5); replicated in Knight ADRC/WashU (n=219)", "n_participants": 998, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Brain 148(2):416-431", "url": "https://doi.org/10.1093/brain/awae346", "doi": "10.1093/brain/awae346", "pubmed_id": "39468767", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Immunoassays as a group: accuracy 0.83-0.88, sensitivity 84-87%, specificity 85-89% for Aβ-PET; assay-specific values not in abstract (null). ALZpath AUC higher than Janssen for Aβ-PET; lower than Lilly for tau-PET.", "evidence_strength": "high (large head-to-head with PET reference, external replication)" }, { "id": "ptau217-janssen-simoa-warmenhoven2025-h2h", "assay_name": "Janssen Simoa plasma p-tau217", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Warmenhoven et al. 2025, Brain (head-to-head of key plasma p-tau217 tests)", "cohort": "BioFINDER-2 (n=998, CU and CI, mean age 68.5); replicated in Knight ADRC/WashU (n=219)", "n_participants": 998, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Brain 148(2):416-431", "url": "https://doi.org/10.1093/brain/awae346", "doi": "10.1093/brain/awae346", "pubmed_id": "39468767", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Lowest AUC among the p-tau217 immunoassays for Aβ-PET status (significantly below Lilly and ALZpath, Pdiff<0.006). Assay-specific values not in abstract (null); group range accuracy 0.83-0.88.", "evidence_strength": "high (large head-to-head with PET reference, external replication)" }, { "id": "ptau217-nulisa-warmenhoven2025-h2h", "assay_name": "Alamar NULISA plasma p-tau217", "analyte": "p-tau217", "platform": "other", "sample_type": "plasma", "study_name": "Warmenhoven et al. 2025, Brain (head-to-head of key plasma p-tau217 tests)", "cohort": "BioFINDER-2 (n=998, CU and CI, mean age 68.5); replicated in Knight ADRC/WashU (n=219)", "n_participants": 998, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Brain 148(2):416-431", "url": "https://doi.org/10.1093/brain/awae346", "doi": "10.1093/brain/awae346", "pubmed_id": "39468767", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Measured only in subsets of both cohorts; abstract states performance similar to the other immunoassays. No numbers in abstract (null).", "evidence_strength": "high (large head-to-head with PET reference, external replication)" }, { "id": "ptau217-lilly-msd-brum2023-twostep", "assay_name": "Eli Lilly MSD plasma p-tau217 (model with age + APOE ε4)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Brum et al. 2023, Nature Aging (two-step workflow)", "cohort": "BioFINDER-1 (development) and BioFINDER-2 (validation) MCI patients, n=348 combined; TRIAD n=84 secondary", "n_participants": 348, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.943, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2023, "publication": "Nature Aging 3:1079-1090", "url": "https://doi.org/10.1038/s43587-023-00471-5", "doi": "10.1038/s43587-023-00471-5", "pubmed_id": "37653254", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.893 in BioFINDER-1 (development), 0.943 in BioFINDER-2 (validation; recorded). Model includes age and APOE ε4, not p-tau217 alone. Two-step workflow overall accuracy 88.2/90.5/92.0% with lenient/moderate/stringent thresholds while reducing CSF tests by 85.9/72.7/61.2%.", "evidence_strength": "moderate-high (validated in independent cohort; MCI only)" }, { "id": "ptau217-lilly-msd-mattssoncarlgren2024", "assay_name": "Eli Lilly MSD plasma p-tau217 (research assay)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Mattsson-Carlgren et al. 2024, JAMA Neurology", "cohort": "BioFINDER-2 participants with cognitive concerns (n=912; 80/20 train/test split); independent validation n=118", "n_participants": 912, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 94, "specificity_pct": 86, "auc": 0.94, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "JAMA Neurology 81(1):69-78", "url": "https://doi.org/10.1001/jamaneurol.2023.4596", "doi": "10.1001/jamaneurol.2023.4596", "pubmed_id": "38048096", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Test-set AUC 0.94 (95% CI 0.90-0.97) for Aβ positivity (Aβ-PET or CSF Aβ42/40). Sensitivity 0.94 (0.90-0.98) and specificity 0.86 (0.77-0.95) are for the 2-cut-point procedure where 17.1% ambiguous cases were resolved with CSF/PET, so they are not stand-alone blood-test values. Tau-PET high load among Aβ+: AUC 0.92 (0.86-0.97).", "evidence_strength": "moderate-high" }, { "id": "ptau181-ugot-simoa-karikari2020", "assay_name": "University of Gothenburg in-house Simoa plasma p-tau181", "analyte": "p-tau181", "platform": "Simoa", "sample_type": "plasma", "study_name": "Karikari et al. 2020, Lancet Neurology", "cohort": "Discovery (n=37), TRIAD (n=226), BioFINDER-2 (n=763), Montreal primary care cohort (n=105); total n=1131", "n_participants": 1131, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.7614, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2020, "publication": "Lancet Neurology 19(5):422-433", "url": "https://doi.org/10.1016/S1474-4422(20)30071-5", "doi": "10.1016/s1474-4422(20)30071-5", "pubmed_id": "32333900", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Amyloid-PET positivity AUC range 76.14-88.09% across cohorts (lower bound recorded); tau-PET AUC 83.08-93.11%. AD dementia vs CU older adults AUC 90.21-98.24%; vs FTD 82.76-100%. In the primary care cohort p-tau181 did NOT discriminate AD from MCI (AUC 55.00%). Early evidence that p-tau181 is weaker than p-tau217 for amyloid status.", "evidence_strength": "moderate-high (4 cohorts)" }, { "id": "ab4240-washu-ipms-schindler2019", "assay_name": "Washington University IP-LC-MS plasma Aβ42/Aβ40 (precursor of C2N PrecivityAD)", "analyte": "Aβ42/40 ratio", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Schindler et al. 2019, Neurology", "cohort": "Knight ADRC, 158 mostly cognitively normal individuals with amyloid PET within 18 months", "n_participants": 158, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.88, "ppv_pct": null, "npv_pct": null, "cutoff_value": 0.1218, "cutoff_units": "Aβ42/Aβ40 ratio (positive if below)", "year": 2019, "publication": "Neurology 93(17):e1647-e1659", "url": "https://doi.org/10.1212/WNL.0000000000008081", "doi": "10.1212/wnl.0000000000008081", "pubmed_id": "31371569", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.88 (95% CI 0.82-0.93) vs amyloid-PET; 0.85 (0.79-0.92) vs CSF p-tau181/Aβ42. With age + APOE ε4: AUC 0.94 (0.90-0.97). Class II evidence. Research volunteers, cognitively normal.", "evidence_strength": "moderate (single center, small)" }, { "id": "ab-composite-ipms-nakamura2018", "assay_name": "Shimadzu IP-MS plasma Aβ composite (APP669-711/Aβ42 + Aβ40/Aβ42)", "analyte": "Aβ42/40 ratio", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Nakamura et al. 2018, Nature", "cohort": "NCGG Japan discovery (n=121) and AIBL Australia validation (n=252; 111 with PiB-PET)", "n_participants": 373, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.941, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2018, "publication": "Nature 554:249-254", "url": "https://doi.org/10.1038/nature25456", "doi": "10.1038/nature25456", "pubmed_id": "29420472", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Composite biomarker AUC 96.7% (discovery, n=121) and 94.1% (validation with PiB-PET, n=111; recorded); accuracy ~90%. Includes CN, MCI and AD. The composite is a ratio-based Aβ measure, not a pure Aβ42/40 ratio.", "evidence_strength": "moderate-high (independent validation)" }, { "id": "gfap-simoa-benedet2021", "assay_name": "Simoa plasma GFAP (Quanterix)", "analyte": "GFAP", "platform": "Simoa", "sample_type": "plasma", "study_name": "Benedet et al. 2021, JAMA Neurology", "cohort": "TRIAD (n=300), ALFA+ (n=384), BioCogBank Paris (n=187)", "n_participants": 871, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.69, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(12):1471-1483", "url": "https://doi.org/10.1001/jamaneurol.2021.3671", "doi": "10.1001/jamaneurol.2021.3671", "pubmed_id": "34661615", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Plasma GFAP AUC for Aβ-positive vs Aβ-negative 0.69-0.86 across cohorts (lower bound recorded); CSF GFAP 0.59-0.76. Reference was amyloid PET in TRIAD/ALFA+ and CSF in Paris. GFAP is a marker of astrogliosis, not AD-specific; accuracy is well below p-tau217.", "evidence_strength": "moderate" }, { "id": "ptau217-lumipulse-arranz2024", "assay_name": "Fujirebio Lumipulse G pTau217 plasma (fully automated)", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Arranz et al. 2024, Alzheimer's Research & Therapy", "cohort": "Sant Pau memory clinic, 290 consecutive patients with lumbar puncture (66 CU, 130 MCI, 94 dementia)", "n_participants": 290, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.94, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Alzheimer's Research & Therapy 16:139", "url": "https://doi.org/10.1186/s13195-024-01513-9", "doi": "10.1186/s13195-024-01513-9", "pubmed_id": "38926773", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.94 (95% CI 0.92-0.97) for CSF-defined amyloid positivity; 4-7% misclassification; two-threshold global accuracy >90% in symptomatic groups. CKD raised concentrations. Stand-alone p-tau217 assay, not the FDA-cleared p-tau217/Aβ42 ratio.", "evidence_strength": "moderate (single center, consecutive real-world sample)" }, { "id": "ptau181-lumipulse-arranz2024", "assay_name": "Fujirebio Lumipulse G pTau181 plasma", "analyte": "p-tau181", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Arranz et al. 2024, Alzheimer's Research & Therapy", "cohort": "Sant Pau memory clinic, 290 consecutive patients with lumbar puncture (66 CU, 130 MCI, 94 dementia)", "n_participants": 290, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.88, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Alzheimer's Research & Therapy 16:139", "url": "https://doi.org/10.1186/s13195-024-01513-9", "doi": "10.1186/s13195-024-01513-9", "pubmed_id": "38926773", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.88 (95% CI 0.84-0.92) vs CSF amyloid status; plasma-CSF correlation rho 0.66.", "evidence_strength": "moderate (single center, consecutive real-world sample)" }, { "id": "ab4240-lumipulse-arranz2024", "assay_name": "Fujirebio Lumipulse G plasma Aβ1-42/Aβ1-40", "analyte": "Aβ42/40 ratio", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Arranz et al. 2024, Alzheimer's Research & Therapy", "cohort": "Sant Pau memory clinic, 290 consecutive patients with lumbar puncture (66 CU, 130 MCI, 94 dementia)", "n_participants": 290, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.88, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Alzheimer's Research & Therapy 16:139", "url": "https://doi.org/10.1186/s13195-024-01513-9", "doi": "10.1186/s13195-024-01513-9", "pubmed_id": "38926773", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.88 (95% CI 0.84-0.92) vs CSF amyloid status; plasma-CSF correlation rho 0.69. Ratios less affected by CKD than single analytes.", "evidence_strength": "moderate (single center, consecutive real-world sample)" }, { "id": "ptau217-lumipulse-alzpath-figdore2024-cutpoints", "assay_name": "Fujirebio Lumipulse G pTau217 and ALZpath pTau217 (two assays, Mayo Clinic clinical lab)", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Figdore et al. 2024, Alzheimer's & Dementia", "cohort": "Mayo Clinic participants with MCI or mild dementia, n=427", "n_participants": 427, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": 92, "specificity_pct": 96, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Alzheimer's & Dementia 20(10):6506-6516", "url": "https://doi.org/10.1002/alz.14140", "doi": "10.1002/alz.14140", "pubmed_id": "39030981", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "IMPORTANT CAVEAT: with a single cutpoint NEITHER assay achieved >=90% in both sensitivity and specificity. The 92%/96% recorded are for a two-cutpoint approach that leaves 20% (Lumipulse) and 39% (ALZpath) of results indeterminate. Platform field set to Lumipulse but row covers both assays.", "evidence_strength": "moderate-high (clinical lab, PET reference)" }, { "id": "ptau217-ab42-lumipulse-piura2026-preclinical-diverse", "assay_name": "Fujirebio Lumipulse G pTau217 and pTau217/Aβ42 ratio", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Piura et al. 2026, Alzheimer's & Dementia", "cohort": "Mayo Clinic Florida cognitively normal participants: 57 Black, 46 Hispanic White, 88 non-Hispanic White (n=191)", "n_participants": 191, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": 83, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": 93, "cutoff_value": 0.132, "cutoff_units": "pg/mL (p-tau217, preclinical-optimized); ratio cutoff 0.0059", "year": 2026, "publication": "Alzheimer's & Dementia (2026), e71763", "url": "https://doi.org/10.1002/alz.71763", "doi": "10.1002/alz.71763", "pubmed_id": "42619350", "fda_clearance": "cleared", "fda_clearance_date": "2025-05-16", "value_type": "measured", "notes": "Preclinical AD (amyloid-PET >=25 Centiloids) in cognitively normal, ethnoracially diverse sample. Cutoffs derived in symptomatic patients gave sensitivity only 57% (p-tau217) and 63% (ratio); cohort-optimized cutoffs raised sensitivity to 83% and 77%; NPV >93% (recorded as 93, lower bound). Evidence that symptomatic-population cutoffs under-detect preclinical amyloid. FDA clearance applies to the ratio in symptomatic patients >=55, not this preclinical use.", "evidence_strength": "moderate (small, cutoffs optimized in same cohort = optimistic)" }, { "id": "ptau217-ab42-ratio-lumipulse-fda-510k-2025", "assay_name": "Fujirebio Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "FDA 510(k) clearance clinical study (FDA press release, 16 May 2025)", "cohort": "Multi-center clinical study, 499 plasma samples from cognitively impaired adults >=55 y (specialized care setting)", "n_participants": 499, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": 97.6, "specificity_pct": 90.8, "auc": null, "ppv_pct": 91.8, "npv_pct": 97.3, "cutoff_value": 0.00738, "cutoff_units": "pTau217/Aβ42 plasma ratio: Positive >=0.00738; Negative <=0.00370; Indeterminate 0.00371-0.00737", "year": 2025, "publication": "FDA 510(k) Decision Summary K242706 (Lumipulse G pTau217/β-Amyloid 1-42 Plasma Ratio); FDA press release 16 May 2025", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf24/K242706.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2025-05-16", "value_type": "measured", "notes": "First FDA-cleared blood test for AD (510(k), Breakthrough Device; predicate = Lumipulse CSF Aβ42/40 ratio). Reference = amyloid PET or CSF. PPV 91.7%, NPV 97.3%; <20% of 499 patients received an indeterminate result (PPV/NPV exclude indeterminates). Sensitivity/specificity/AUC not stated in press release. Intended for symptomatic patients >=55 in specialized care; not a screening or stand-alone test. openFDA 510(k) record: K242706, decision date 2025-05-16, applicant Fujirebio Diagnostics, Inc. Predicate Lumipulse G β-Amyloid Ratio (1-42/1-40) CSF was De Novo DEN200072 (2022-05-04). FROM 510(k) SUMMARY K242706 pivotal 2x2 (n=499, PET or CSF reference, prevalence 51.1%): Positive 201 PET/CSF+ vs 18 neg (PV 91.8%, 95% CI 87.8-94.6); Indeterminate 49/49 (19.6% of results); Negative 5 pos vs 177 neg (PV of negative for positivity 2.7%, i.e. NPV 97.3%). Sensitivity 97.6% (201/206) and specificity 90.8% (177/195) are DERIVED here from the FDA 2x2 after excluding indeterminates; FDA summary itself reports predictive values and likelihood ratios (LR+ 10.68, LR- 0.03), not sens/spec. Cohorts: AriBio Polaris-AD phase III screening, BioFINDER-2 (Malmö), Bio-Hermes-001, WRAP. Mean age 72, 84.8% white; 58.2% clinically AD dementia, 40.7% SCD/MCI. Cutoffs derived in separate 208-sample set (PV+ 94.6%, prevalence 54.8%).", "evidence_strength": "high (regulatory pivotal study) but PPV/NPV depend on ~study prevalence" }, { "id": "pctptau217-c2n-precivityad2-fnih2024", "assay_name": "C2N PrecivityAD2 %p-tau217 (mass-spec)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 88.5, "specificity_pct": 87.1, "auc": 0.927, "ppv_pct": 86.7, "npv_pct": 88.8, "cutoff_value": 4.06, "cutoff_units": "% p-tau217 (positive if above)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.927 (95% CI 0.900-0.955). Sensitivity/specificity recorded as PPA/NPA at cutoff 4.06%; overall accuracy 87.8%. Adding Aβ42/40 (APS2) gave AUC 0.929, not significantly better (p=0.54). 110/392 samples were below the assay's p-tau217 limit of detection. Cutoff 4.06% is Youden-optimal in this cohort (prevalence 48.7%).", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "aps2-c2n-precivityad2-fnih2024", "assay_name": "C2N PrecivityAD2 APS2 (%p-tau217 + Aβ42/Aβ40 combined model)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.929, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.929 (0.902-0.956), highest of any test in the study; not superior to %p-tau217 alone (p=0.54).", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau217-c2n-precivityad2-fnih2024", "assay_name": "C2N PrecivityAD2 p-tau217 concentration (mass-spec, non-ratio)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 86.4, "specificity_pct": 87.1, "auc": 0.916, "ppv_pct": 86.4, "npv_pct": 87.1, "cutoff_value": 2.34, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.916 (0.887-0.946). Ratio form (%p-tau217) performed slightly better. Table 4 (Youden cutoff 2.34 pg/mL): PPA 86.4%, NPA 87.1%, accuracy 86.7%, PPV 86.4%, NPV 87.1%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ab4240-c2n-precivityad2-fnih2024", "assay_name": "C2N PrecivityAD2 Aβ42/Aβ40 (mass-spec)", "analyte": "Aβ42/40 ratio", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 71.7, "specificity_pct": 67.2, "auc": 0.751, "ppv_pct": 67.5, "npv_pct": 71.4, "cutoff_value": 0.0924, "cutoff_units": "Aβ42/Aβ40 ratio (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "LDT-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.751 (0.703-0.799); median only 10.6% lower in PET+ group. Key finding: plasma Aβ42/40 had relatively low accuracy on every platform. Table 4: PPA 71.7%, NPA 67.2%, accuracy 69.4%, PPV 67.5%, NPV 71.4%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau217-ab4240-lumipulse-fnih2024", "assay_name": "Fujirebio Lumipulse p-tau217 + Aβ42/Aβ40 combined model", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.911, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.911 (0.882-0.940); not significantly different from C2N combined model (p=0.16). Note this is a p-tau217 + Aβ42/40 model, not the later FDA-cleared p-tau217/Aβ42 ratio.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau217-lumipulse-fnih2024", "assay_name": "Fujirebio Lumipulse G pTau217 plasma", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 84.3, "specificity_pct": 82.1, "auc": 0.896, "ppv_pct": 81.7, "npv_pct": 84.6, "cutoff_value": 0.158, "cutoff_units": "pg/mL (positive if above)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.896 (0.864-0.928). At cutoff 0.158 pg/mL: PPA 84.3%, NPA 82.1%, accuracy 83.2%, PPV 81.7%, NPV 84.6%. Assay CV was 11% and 34% for high and low controls (higher imprecision than other assays). Table 4 accuracy 83.2%. Cutoff is Youden-optimal in this cohort.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ab4240-lumipulse-fnih2024", "assay_name": "Fujirebio Lumipulse plasma Aβ42/Aβ40", "analyte": "Aβ42/40 ratio", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 72.3, "specificity_pct": 75.1, "auc": 0.787, "ppv_pct": 73.4, "npv_pct": 74.0, "cutoff_value": 0.0869, "cutoff_units": "Aβ42/Aβ40 ratio (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.787 (0.741-0.833). Table 4: PPA 72.3%, NPA 75.1%, accuracy 73.7%, PPV 73.4%, NPV 74.0%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau217-alzpath-quanterix-fnih2024", "assay_name": "ALZpath pTau217 (Quanterix Simoa)", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 84.3, "specificity_pct": 83.1, "auc": 0.885, "ppv_pct": 82.6, "npv_pct": 84.8, "cutoff_value": 0.444, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.885 (0.851-0.920); significantly lower than C2N combined model (p=0.0006). Table 4: PPA 84.3%, NPA 83.1%, accuracy 83.7%, PPV 82.6%, NPV 84.8%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau217-janssen-lucentad-quanterix-fnih2024", "assay_name": "Janssen LucentAD p-tau217 (Quanterix Simoa)", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 80.6, "specificity_pct": 83.1, "auc": 0.882, "ppv_pct": 81.9, "npv_pct": 81.9, "cutoff_value": 0.0615, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.882 (0.848-0.916); significantly lower than C2N (p=0.0006). Table 4: PPA 80.6%, NPA 83.1%, accuracy 81.9%, PPV 81.9%, NPV 81.9%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau181-roche-ntk-fnih2024", "assay_name": "Roche NeuroToolKit plasma p-tau181 (Elecsys prototype, research)", "analyte": "p-tau181", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 77.5, "specificity_pct": 74.6, "auc": 0.815, "ppv_pct": 74.4, "npv_pct": 77.7, "cutoff_value": 1.14, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.815 (0.772-0.858). Roche 4-analyte panel (p-tau181+Aβ42/40+GFAP+NfL) AUC 0.873 (0.838-0.909). Table 4: PPA 77.5%, NPA 74.6%, accuracy 76.0%, PPV 74.4%, NPV 77.7%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ab4240-roche-ntk-fnih2024", "assay_name": "Roche NeuroToolKit plasma Aβ42/Aβ40 (Elecsys prototype)", "analyte": "Aβ42/40 ratio", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 86.4, "specificity_pct": 62.7, "auc": 0.775, "ppv_pct": 68.8, "npv_pct": 82.9, "cutoff_value": 0.126, "cutoff_units": "Aβ42/Aβ40 ratio (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.775 (0.728-0.823). Table 4: PPA 86.4%, NPA 62.7%, accuracy 74.2%, PPV 68.8%, NPV 82.9%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "gfap-roche-ntk-fnih2024", "assay_name": "Roche NeuroToolKit plasma GFAP (Elecsys prototype)", "analyte": "GFAP", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 72.8, "specificity_pct": 68.2, "auc": 0.758, "ppv_pct": 68.5, "npv_pct": 72.5, "cutoff_value": 0.113, "cutoff_units": "ng/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.758 (0.710-0.806); median 64% higher in PET+ group. Table 4: PPA 72.8%, NPA 68.2%, accuracy 70.4%, PPV 68.5%, NPV 72.5%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "nfl-roche-ntk-fnih2024", "assay_name": "Roche NeuroToolKit plasma NfL (Elecsys prototype)", "analyte": "NfL", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 392, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 59.2, "specificity_pct": 68.2, "auc": 0.677, "ppv_pct": 63.8, "npv_pct": 63.7, "cutoff_value": 4.29, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.677 (0.624-0.729) - lowest of all analytes; NfL is a nonspecific neurodegeneration marker, not an amyloid marker. Table 4: PPA 59.2%, NPA 68.2%, accuracy 63.8%, PPV 63.8%, NPV 63.7%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau181-quanterix-n4plex-fnih2024", "assay_name": "Quanterix Neurology 4-Plex plasma p-tau181 (Simoa)", "analyte": "p-tau181", "platform": "Simoa", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 342, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 71.7, "specificity_pct": 69.4, "auc": 0.747, "ppv_pct": 67.1, "npv_pct": 73.8, "cutoff_value": 20.5, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.747 (0.694-0.799) in n=342 subcohort. Table 4: PPA 71.7%, NPA 69.4%, accuracy 70.5%, PPV 67.1%, NPV 73.8%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "gfap-quanterix-n4plex-fnih2024", "assay_name": "Quanterix Neurology 4-Plex plasma GFAP (Simoa)", "analyte": "GFAP", "platform": "Simoa", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 342, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 59.7, "specificity_pct": 81.4, "auc": 0.756, "ppv_pct": 73.6, "npv_pct": 70.0, "cutoff_value": 205, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.756 (0.704-0.807) in n=342 subcohort. Table 4: PPA 59.7%, NPA 81.4%, accuracy 71.3%, PPV 73.6%, NPV 70.0%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "nfl-quanterix-n4plex-fnih2024", "assay_name": "Quanterix Neurology 4-Plex plasma NfL (Simoa)", "analyte": "NfL", "platform": "Simoa", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 342, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 68.6, "specificity_pct": 57.4, "auc": 0.67, "ppv_pct": 58.3, "npv_pct": 67.7, "cutoff_value": 21.7, "cutoff_units": "pg/mL (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.670 (0.613-0.727) in n=342 subcohort; covariates-only model (age, sex, APOE) had AUC 0.733, i.e. NfL alone is worse than demographics. Table 4: PPA 68.6%, NPA 57.4%, accuracy 62.6%, PPV 58.3%, NPV 67.7%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ab4240-quanterix-n4plex-fnih2024", "assay_name": "Quanterix Neurology 4-Plex plasma Aβ42/Aβ40 (Simoa)", "analyte": "Aβ42/40 ratio", "platform": "Simoa", "sample_type": "plasma", "study_name": "Schindler et al. 2024, Alzheimer's & Dementia (FNIH Biomarkers Consortium head-to-head of leading blood tests)", "cohort": "ADNI, n=392 (median age 78.1; 48.7% amyloid-PET+; 49% cognitively impaired); Quanterix Neurology 4-Plex on subcohort n=342", "n_participants": 342, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 73.0, "specificity_pct": 68.9, "auc": 0.734, "ppv_pct": 67.1, "npv_pct": 74.6, "cutoff_value": 0.0582, "cutoff_units": "Aβ42/Aβ40 ratio (Youden cutoff)", "year": 2024, "publication": "Alzheimer's & Dementia 20(11):8074-8096", "url": "https://doi.org/10.1002/alz.14315", "doi": "10.1002/alz.14315", "pubmed_id": "39394841", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Unadjusted AUC for amyloid-PET status (Centiloid >20) from Table 3; AUC 0.734 (0.681-0.787) in n=342 subcohort. Table 4: PPA 73.0%, NPA 68.9%, accuracy 70.8%, PPV 67.1%, NPV 74.6%.", "evidence_strength": "high (independent consortium, blinded head-to-head, PET reference); ADNI is a highly selected research cohort, 93% white" }, { "id": "ptau217-lilly-msd-thijssen2021-amyloidpet", "assay_name": "Eli Lilly MSD plasma p-tau217", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Thijssen et al. 2021, Lancet Neurology", "cohort": "UCSF Memory and Aging Center (n=443) and ARTFL consortium (n=150); total n=593, mean age 64", "n_participants": 146, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.91, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "Lancet Neurology 20(9):739-752", "url": "https://doi.org/10.1016/S1474-4422(21)00214-3", "doi": "10.1016/s1474-4422(21)00214-3", "pubmed_id": "34418401", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Amyloid-PET positivity AUC 0.91 (95% CI 0.88-0.94), n=146; vs p-tau181 0.89 (Pdiff=0.049). AD syndromes vs CU: AUC 0.98; AD syndromes vs FTLD syndromes 0.93 (0.91-0.96).", "evidence_strength": "moderate-high (multicohort; young cohort mean age 64, FTLD-enriched)" }, { "id": "ptau181-lilly-msd-thijssen2021-amyloidpet", "assay_name": "Eli Lilly MSD plasma p-tau181", "analyte": "p-tau181", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Thijssen et al. 2021, Lancet Neurology", "cohort": "UCSF Memory and Aging Center (n=443) and ARTFL consortium (n=150); total n=593, mean age 64", "n_participants": 214, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.89, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "Lancet Neurology 20(9):739-752", "url": "https://doi.org/10.1016/S1474-4422(21)00214-3", "doi": "10.1016/s1474-4422(21)00214-3", "pubmed_id": "34418401", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Amyloid-PET positivity AUC 0.89 (0.86-0.93), n=214. AD syndromes vs CU AUC 0.97; vs FTLD syndromes 0.91 (0.88-0.94).", "evidence_strength": "moderate-high (multicohort; young cohort mean age 64, FTLD-enriched)" }, { "id": "ptau217-lilly-msd-thijssen2021-autopsy", "assay_name": "Eli Lilly MSD plasma p-tau217", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Thijssen et al. 2021, Lancet Neurology", "cohort": "UCSF Memory and Aging Center (n=443) and ARTFL consortium (n=150); total n=593, mean age 64", "n_participants": 83, "population": "memory-clinic", "comparator": "autopsy", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.96, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "Lancet Neurology 20(9):739-752", "url": "https://doi.org/10.1016/S1474-4422(21)00214-3", "doi": "10.1016/s1474-4422(21)00214-3", "pubmed_id": "34418401", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Pathology-confirmed AD (n=15) vs pathology-confirmed FTLD (n=68): AUC 0.96 (0.92-1.00) for p-tau217 vs 0.91 (0.82-1.00) for p-tau181 (Pdiff=0.22, not significant). Very small autopsy sample.", "evidence_strength": "moderate-high (multicohort; young cohort mean age 64, FTLD-enriched)" }, { "id": "nfl-simoa-ashton2021-multicentre", "assay_name": "Simoa plasma NfL (Quanterix)", "analyte": "NfL", "platform": "Simoa", "sample_type": "plasma", "study_name": "Ashton et al. 2021, Nature Communications", "cohort": "King's College London (n=805) and BioFINDER (n=1,464); 13 neurodegenerative disorders, Down syndrome, depression, controls", "n_participants": 2269, "population": "mixed", "comparator": "clinical-diagnosis", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "Nature Communications 12:3400", "url": "https://doi.org/10.1038/s41467-021-23620-z", "doi": "10.1038/s41467-021-23620-z", "pubmed_id": "34099648", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "NfL is a nonspecific neurodegeneration marker: useful for atypical parkinsonism vs PD, dementia in Down syndrome, dementia vs psychiatric disorders, FTD vs other cognitive impairment; not for AD-specific diagnosis. Abstract gives no AUC (null); 'performs best when applied to indicate no underlying neurodegeneration'. Age-specific cutoffs required.", "evidence_strength": "high (large multicentre)" }, { "id": "ptau181-elecsys-roche-fda-510k-2025", "assay_name": "Roche Elecsys pTau181 plasma (cobas; developed with Eli Lilly)", "analyte": "p-tau181", "platform": "Elecsys", "sample_type": "plasma", "study_name": "FDA 510(k) clearance clinical study (Roche investor update, 13 Oct 2025)", "cohort": "Multicenter non-interventional study, 312 participants >=55 y with cognitive complaints; early-stage, low-prevalence population reflective of primary care", "n_participants": 312, "population": "primary-care", "comparator": "amyloid-PET", "sensitivity_pct": 92.7, "specificity_pct": 51.3, "auc": null, "ppv_pct": 22.4, "npv_pct": 97.9, "cutoff_value": 0.722, "cutoff_units": "pg/mL (positive if >0.722)", "year": 2025, "publication": "FDA 510(k) Summary K252163 (Elecsys Phospho-Tau (181P) Plasma); Roche investor update 13 Oct 2025", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf25/K252163.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2025-10-08", "value_type": "measured", "notes": "Second FDA-cleared AD blood test; first indicated for primary care; RULE-OUT only. Press release states NPV 97.9% and nothing else (no sensitivity, specificity, PPV, AUC, or reference-standard detail beyond 'Alzheimer's-related amyloid pathology'). NPV in a low-prevalence population is inherently high; PPV was not disclosed. Also CE-marked (IVDR). openFDA 510(k) record: K252163 Elecsys Phospho-Tau (181P) Plasma, decision date 2025-10-08 (Roche announced 2025-10-13). FROM 510(k) SUMMARY K252163 (Roche study RD006263, prospective, 8 sites: 6 US, 2 EU; 95.8% US): n=312, mean age 69.1 (55-80), 59% white, 34% Black; 41% SCD, 56% MCI, 1% mild dementia. Reference = amyloid PET visual read (3-reader majority); PET prevalence only 13.1% (41/312). At cutoff 0.722 pg/mL: PPA 92.7% (38/41; 80.6-97.5), NPA 51.3% (139/271; 45.4-57.2), TPA 56.7%, PPV 22.4% (38/170), NPV 97.9% (139/142; 94.5-99.3), LR+ 1.90, LR- 0.143, rule-out rate 45.5%. KEY CAVEAT: the headline 97.9% NPV arises mostly from the 13% prevalence; specificity is 51% and PPV 22%, so a positive result is more often wrong than right.", "evidence_strength": "moderate (company press release; pivotal data not peer-reviewed at time of capture)" }, { "id": "ptau217-elecsys-roche-fda-510k-2026", "assay_name": "Roche Elecsys Phospho-Tau (217P) Plasma (pTau217; developed with Eli Lilly)", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "FDA 510(k) clearance (Roche investor update, 24 Aug 2026)", "cohort": "Individuals >=55 y with signs, symptoms or complaints of cognitive decline (clearance study details not disclosed in release)", "n_participants": null, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "Roche investor update: Roche receives FDA clearance for Elecsys pTau217", "url": "https://www.roche.com/investors/updates/inv-update-2026-08-24", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured", "notes": "Fourth FDA-cleared AD blood test; first single-biomarker test cleared for both rule-in and rule-out with the same cutoffs across primary and specialty care; three result categories (positive/intermediate/negative). Press release gives NO performance numbers, only 'high agreement with amyloid PET imaging'. Not stand-alone. See separate row for the prototype-assay clinical-cohort study (Hibar 2026). openFDA 510(k) record: K261686 Elecsys Phospho-Tau (217P) Plasma, decision date 2026-08-19 (Roche announced 2026-08-24).", "evidence_strength": "low for numbers (none disclosed); regulatory clearance itself verified" }, { "id": "aps2-c2n-precivityad2-fda-510k-2026", "assay_name": "C2N PrecivityAD2 (APS2: HRMS %p-tau217 + Aβ42/40), FDA-cleared IVD version", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "FDA 510(k) clearance clinical validation study (C2N press release, 20 Aug 2026)", "cohort": "Pooled Validation Cohort, 3 cohorts, n=1,142 adults >=40 with cognitive symptoms (21.2% SCD, 47.3% MCI, 31.5% dementia); amyloid prevalence 52.7%", "n_participants": 1142, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 92.0, "specificity_pct": 98.0, "auc": null, "ppv_pct": 97.6, "npv_pct": 93.1, "cutoff_value": 66.5, "cutoff_units": "APS2 score: Positive >66.5; Negative <27.5; Likely Positive 27.5-66.5", "year": 2026, "publication": "FDA 510(k) Summary K253240 (PrecivityAD2 Test); C2N press release 20 Aug 2026", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf25/K253240.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured", "notes": "Third FDA-cleared AD blood test; only one indicated from age 40; first HRMS-based. Reference = amyloid PET visual read or CSF biomarkers. Dual cutoffs: Positive result PPV 97.6%, Negative result NPV 93.1%; a 'Likely Positive' intermediate category occurred in 17.3% of subjects with PPV 77.3%. Sensitivity/specificity/AUC not disclosed. Performance reported as consistent across 12 chronic comorbidities incl. CKD. FDA-cleared version expected available later in 2026; CLIA LDT version already offered. openFDA 510(k): K253240 PrecivityAD2 Test, C2N Diagnostics, LLC, decision date 2026-08-19 (C2N announced 2026-08-20). FROM 510(k) SUMMARY K253240 Table 53.24 (reference = amyloid PET visual read n=209 or Lumipulse CSF Aβ42/40 n=933): Positive 413 present/10 absent (PPV 97.6%, 95.7-98.7; 37.0% of results; LR+ 37.05); Likely Positive 153/45 (PV 77.3%; 17.3% of results); Negative 36/485 (PV 6.9% => NPV 93.1%; 45.6% of results; LR- 0.07). Sensitivity 92.0% (413/449) and specificity 98.0% (485/495) are DERIVED here from the FDA 2x2 excluding Likely Positive; FDA reports predictive values, not sens/spec. Performance similar across SCD (PPV 90.3%, prevalence 24.0%), MCI (97.9%) and dementia (98.5%). PET-visual-read-only subset (n=209): PPV 90.5%, Likely Positive PV 57.5%, NPV 93.7%; CSF-only subset (n=933): PPV 99.1%, NPV 93.0%. Note 82% of the reference standard was CSF, not PET.", "evidence_strength": "moderate (company press release; PPV/NPV depend on study prevalence, not disclosed)" }, { "id": "amyloid-pet-florbetapir-clark2011-autopsy", "assay_name": "Florbetapir F18 amyloid PET (Amyvid), visual read", "analyte": "amyloid-PET", "platform": "other", "sample_type": "plasma", "study_name": "Clark et al. 2011, JAMA (AV45-A07 autopsy study)", "cohort": "End-of-life patients from hospice/long-term care (n=29 primary autopsy cohort; 35 autopsied) plus 74 young controls", "n_participants": 29, "population": "mixed", "comparator": "autopsy", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2011, "publication": "JAMA 305(3):275-283", "url": "https://doi.org/10.1001/jama.2010.2008", "doi": "10.1001/jama.2010.2008", "pubmed_id": "21245183", "fda_clearance": "cleared", "fda_clearance_date": null, "value_type": "measured", "notes": "BENCHMARK for the 'approaches amyloid-PET accuracy' claim. Visual PET read agreed with postmortem amyloid status in 96% of 29 individuals; correlation with immunohistochemistry rho 0.78. Sensitivity/specificity not reported in abstract (null). sample_type is not applicable (imaging); set to plasma only to satisfy schema enum. Amyvid FDA approval (2012) date not verified here.", "evidence_strength": "moderate (very small autopsy cohort; later 59-subject cohort not captured)" }, { "id": "tau-pet-flortaucipir-fleisher2020-autopsy", "assay_name": "[18F]flortaucipir tau PET (Tauvid), visual read", "analyte": "tau-PET", "platform": "other", "sample_type": "plasma", "study_name": "Fleisher et al. 2020, JAMA Neurology (A16 autopsy study)", "cohort": "A16 primary cohort: 64 terminally ill patients >50 y with autopsy (mean age 82.5; 77% dementia), 28 sites", "n_participants": 64, "population": "mixed", "comparator": "autopsy", "sensitivity_pct": 92.3, "specificity_pct": 52.0, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2020, "publication": "JAMA Neurology 77(7):829-839", "url": "https://doi.org/10.1001/jamaneurol.2020.0528", "doi": "10.1001/jamaneurol.2020.0528", "pubmed_id": "32338734", "fda_clearance": "cleared", "fda_clearance_date": null, "value_type": "measured", "notes": "BENCHMARK. Prediction of B3 (Braak V/VI) tau pathology across 5 readers: sensitivity 92.3-100% and specificity 52.0-92.0% (lower bounds recorded). High ADNC: sensitivity 94.7-100%, specificity 50.0-92.3%. Shows that even PET 'gold standards' have reader-dependent specificity. sample_type not applicable (imaging). Tauvid FDA approval (2020) date not verified here.", "evidence_strength": "high (prospective autopsy-validated, regulatory)" }, { "id": "csf-ptau181-ab42-elecsys-hansson2018", "assay_name": "Roche Elecsys CSF p-tau181/Aβ42 ratio (fully automated)", "analyte": "p-tau181", "platform": "Elecsys", "sample_type": "CSF", "study_name": "Hansson et al. 2018, Alzheimer's & Dementia", "cohort": "BioFINDER (n=277, flutemetamol PET) for cutoff definition; ADNI (n=646, florbetapir PET) validation", "n_participants": 923, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.94, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2018, "publication": "Alzheimer's & Dementia 14(11):1470-1481", "url": "https://doi.org/10.1016/j.jalz.2018.01.010", "doi": "10.1016/j.jalz.2018.01.010", "pubmed_id": "29499171", "fda_clearance": "cleared", "fda_clearance_date": "2022-12-07", "value_type": "measured", "notes": "BENCHMARK CSF test. BioFINDER: overall percent agreement with PET 90%, AUC 94% (recorded); ADNI validation with predefined cutoffs: OPA 89-90%, AUC 96%. Elecsys CSF p-tau181/Aβ42 later FDA-cleared (2022; date not verified here). Plasma %p-tau217 was judged clinically equivalent to this test in Barthélemy 2024. openFDA 510(k): K221842 Elecsys β-Amyloid (1-42) CSF II / Phospho-Tau (181P) CSF, decision 2022-12-07.", "evidence_strength": "high" }, { "id": "ab4240-washu-ipms-janelidze2021-h2h", "assay_name": "Washington University IP-MS plasma Aβ42/40 (C2N precursor)", "analyte": "Aβ42/40 ratio", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Janelidze et al. 2021, JAMA Neurology (head-to-head of 8 plasma Aβ42/40 assays)", "cohort": "BioFINDER (182 CU + 104 MCI, mean age 71.6); ADNI validation n=122", "n_participants": 286, "population": "mixed", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.86, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(11):1375-1382", "url": "https://doi.org/10.1001/jamaneurol.2021.3180", "doi": "10.1001/jamaneurol.2021.3180", "pubmed_id": "34542571", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.86 (95% CI 0.81-0.90) in whole BioFINDER cohort; significantly better than Araclon LC-MS, Roche Elecsys, Euroimmun and Simoa N4PE immunoassays (AUC 0.69-0.78). Best-performing Aβ assay. Reference = abnormal CSF Aβ42/40 (results 'similar' with Aβ-PET).", "evidence_strength": "high (head-to-head, two cohorts)" }, { "id": "ab4240-shimadzu-ipms-janelidze2021-h2h", "assay_name": "Shimadzu IP-MS plasma Aβ42/40 (Nakamura method)", "analyte": "Aβ42/40 ratio", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Janelidze et al. 2021, JAMA Neurology (head-to-head of 8 plasma Aβ42/40 assays)", "cohort": "BioFINDER (182 CU + 104 MCI, mean age 71.6); ADNI validation n=122", "n_participants": 200, "population": "mixed", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.83, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(11):1375-1382", "url": "https://doi.org/10.1001/jamaneurol.2021.3180", "doi": "10.1001/jamaneurol.2021.3180", "pubmed_id": "34542571", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.83 vs 0.87 for WashU in the n=200 subcohort (P=0.16, not different). Reference = abnormal CSF Aβ42/40 (results 'similar' with Aβ-PET).", "evidence_strength": "high (head-to-head, two cohorts)" }, { "id": "ab4240-roche-elecsys-janelidze2021-h2h", "assay_name": "Roche Elecsys plasma Aβ42/40 (prototype immunoassay)", "analyte": "Aβ42/40 ratio", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Janelidze et al. 2021, JAMA Neurology (head-to-head of 8 plasma Aβ42/40 assays)", "cohort": "BioFINDER (182 CU + 104 MCI, mean age 71.6); ADNI validation n=122", "n_participants": 286, "population": "mixed", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(11):1375-1382", "url": "https://doi.org/10.1001/jamaneurol.2021.3180", "doi": "10.1001/jamaneurol.2021.3180", "pubmed_id": "34542571", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract groups Elecsys with Araclon, Euroimmun and N4PE in AUC range 0.69-0.78; assay-specific value not in abstract (null). Reference = abnormal CSF Aβ42/40 (results 'similar' with Aβ-PET).", "evidence_strength": "high (head-to-head, two cohorts)" }, { "id": "ab4240-quanterix-n4pe-janelidze2021-h2h", "assay_name": "Quanterix Simoa Neurology 4-Plex E plasma Aβ42/40", "analyte": "Aβ42/40 ratio", "platform": "Simoa", "sample_type": "plasma", "study_name": "Janelidze et al. 2021, JAMA Neurology (head-to-head of 8 plasma Aβ42/40 assays)", "cohort": "BioFINDER (182 CU + 104 MCI, mean age 71.6); ADNI validation n=122", "n_participants": 286, "population": "mixed", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(11):1375-1382", "url": "https://doi.org/10.1001/jamaneurol.2021.3180", "doi": "10.1001/jamaneurol.2021.3180", "pubmed_id": "34542571", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Grouped in AUC range 0.69-0.78 (assay-specific value not in abstract). Reference = abnormal CSF Aβ42/40 (results 'similar' with Aβ-PET).", "evidence_strength": "high (head-to-head, two cohorts)" }, { "id": "ab4240-quanterix-ia-janelidze2021-h2h", "assay_name": "Quanterix Simoa (IA-Quan) plasma Aβ42/40", "analyte": "Aβ42/40 ratio", "platform": "Simoa", "sample_type": "plasma", "study_name": "Janelidze et al. 2021, JAMA Neurology (head-to-head of 8 plasma Aβ42/40 assays)", "cohort": "BioFINDER (182 CU + 104 MCI, mean age 71.6); ADNI validation n=122", "n_participants": 227, "population": "mixed", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.64, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(11):1375-1382", "url": "https://doi.org/10.1001/jamaneurol.2021.3180", "doi": "10.1001/jamaneurol.2021.3180", "pubmed_id": "34542571", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.64 vs WashU 0.84 in the n=227 subcohort (P<0.001); UGOT IP-MS 0.68. Reference = abnormal CSF Aβ42/40 (results 'similar' with Aβ-PET).", "evidence_strength": "high (head-to-head, two cohorts)" }, { "id": "ab4240-ugot-ipms-janelidze2021-h2h", "assay_name": "University of Gothenburg IP-MS plasma Aβ42/40", "analyte": "Aβ42/40 ratio", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Janelidze et al. 2021, JAMA Neurology (head-to-head of 8 plasma Aβ42/40 assays)", "cohort": "BioFINDER (182 CU + 104 MCI, mean age 71.6); ADNI validation n=122", "n_participants": 227, "population": "mixed", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.68, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "JAMA Neurology 78(11):1375-1382", "url": "https://doi.org/10.1001/jamaneurol.2021.3180", "doi": "10.1001/jamaneurol.2021.3180", "pubmed_id": "34542571", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.68 vs WashU 0.84 in n=227 subcohort (P<0.001). Reference = abnormal CSF Aβ42/40 (results 'similar' with Aβ-PET).", "evidence_strength": "high (head-to-head, two cohorts)" }, { "id": "ptau217-plasma-meta-khalafi2025", "assay_name": "Plasma p-tau217, pooled across assays (systematic review/meta-analysis)", "analyte": "p-tau217", "platform": "other", "sample_type": "plasma", "study_name": "Khalafi et al. 2025, Alzheimer's & Dementia (meta-analysis, 30 studies, search to Aug 2024)", "cohort": "Pooled studies with PET reference", "n_participants": null, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 82, "specificity_pct": 86, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(2):e14458", "url": "https://doi.org/10.1002/alz.14458", "doi": "10.1002/alz.14458", "pubmed_id": "39711334", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "modelled (pooled meta-analytic estimate)", "notes": "Pooled plasma p-tau217: sensitivity 82%, specificity 86% for amyloid PET; 83%/83% for tau PET. CSF p-tau217: 79%/91% amyloid. Accuracy lower in cognitively unimpaired than impaired. Pooled values are substantially below single-cohort headline AUCs of 0.95+.", "evidence_strength": "high (systematic review) but heterogeneous assays/cutoffs" }, { "id": "ptau217-meta-yuan2026-simoa", "assay_name": "Plasma p-tau217 on Simoa platforms, pooled (meta-analysis)", "analyte": "p-tau217", "platform": "Simoa", "sample_type": "plasma", "study_name": "Yuan et al. 2026, Neurological Sciences (meta-analysis, 25 studies, 18,073 participants, PROSPERO CRD420261371940)", "cohort": "Pooled studies with amyloid-PET reference, Jan 2020-Feb 2026", "n_participants": 18073, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 89.4, "specificity_pct": 87.5, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "Neurological Sciences (2026)", "url": "https://doi.org/10.1007/s10072-026-09322-8", "doi": "10.1007/s10072-026-09322-8", "pubmed_id": "42649434", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "modelled (pooled meta-analytic estimate)", "notes": "Simoa pooled sensitivity 0.894 (0.861-0.920), specificity 0.875 (0.845-0.900). Heterogeneity I2 63-86%. p-tau217/Aβ42 ratio roughly doubled DOR vs p-tau217 alone (relative DOR 1.96, 1.19-3.23) in 5 paired studies.", "evidence_strength": "high (systematic review) but high heterogeneity" }, { "id": "ptau217-meta-yuan2026-clia", "assay_name": "Plasma p-tau217 on CLIA (chemiluminescence, e.g. Lumipulse) platforms, pooled (meta-analysis)", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Yuan et al. 2026, Neurological Sciences (meta-analysis, 25 studies, 18,073 participants, PROSPERO CRD420261371940)", "cohort": "Pooled studies with amyloid-PET reference, Jan 2020-Feb 2026", "n_participants": 18073, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 88.6, "specificity_pct": 86.5, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "Neurological Sciences (2026)", "url": "https://doi.org/10.1007/s10072-026-09322-8", "doi": "10.1007/s10072-026-09322-8", "pubmed_id": "42649434", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "modelled (pooled meta-analytic estimate)", "notes": "CLIA pooled sensitivity 0.886 (0.860-0.907), specificity 0.865 (0.826-0.896). Heterogeneity I2 63-86%. p-tau217/Aβ42 ratio roughly doubled DOR vs p-tau217 alone (relative DOR 1.96, 1.19-3.23) in 5 paired studies.", "evidence_strength": "high (systematic review) but high heterogeneity" }, { "id": "ptau217-meta-yuan2026-eclia", "assay_name": "Plasma p-tau217 on ECLIA (electrochemiluminescence, e.g. Elecsys/MSD) platforms, pooled (meta-analysis)", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Yuan et al. 2026, Neurological Sciences (meta-analysis, 25 studies, 18,073 participants, PROSPERO CRD420261371940)", "cohort": "Pooled studies with amyloid-PET reference, Jan 2020-Feb 2026", "n_participants": 18073, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 93.3, "specificity_pct": 79.1, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "Neurological Sciences (2026)", "url": "https://doi.org/10.1007/s10072-026-09322-8", "doi": "10.1007/s10072-026-09322-8", "pubmed_id": "42649434", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "modelled (pooled meta-analytic estimate)", "notes": "ECLIA pooled sensitivity 0.933 (0.918-0.946), specificity 0.791 (0.571-0.915) - highest sensitivity, lowest specificity, very wide CI. Heterogeneity I2 63-86%. p-tau217/Aβ42 ratio roughly doubled DOR vs p-tau217 alone (relative DOR 1.96, 1.19-3.23) in 5 paired studies.", "evidence_strength": "high (systematic review) but high heterogeneity" }, { "id": "ptau217-meta-yuan2026-lcms", "assay_name": "Plasma p-tau217 on LC-MS/MS platforms, pooled (meta-analysis)", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "Yuan et al. 2026, Neurological Sciences (meta-analysis, 25 studies, 18,073 participants, PROSPERO CRD420261371940)", "cohort": "Pooled studies with amyloid-PET reference, Jan 2020-Feb 2026", "n_participants": 18073, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 82.7, "specificity_pct": 93.8, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "Neurological Sciences (2026)", "url": "https://doi.org/10.1007/s10072-026-09322-8", "doi": "10.1007/s10072-026-09322-8", "pubmed_id": "42649434", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "modelled (pooled meta-analytic estimate)", "notes": "LC-MS/MS pooled sensitivity 0.827 (0.725-0.897), specificity 0.938 (0.692-0.990) - highest specificity; note the wide CIs. Heterogeneity I2 63-86%. p-tau217/Aβ42 ratio roughly doubled DOR vs p-tau217 alone (relative DOR 1.96, 1.19-3.23) in 5 paired studies.", "evidence_strength": "high (systematic review) but high heterogeneity" }, { "id": "ptau217-plasma-meta-gebril2026", "assay_name": "Plasma p-tau217, pooled across assays (Bayesian bivariate meta-analysis)", "analyte": "p-tau217", "platform": "other", "sample_type": "plasma", "study_name": "Gebril et al. 2026, Molecular Neurobiology (meta-analysis, 27 studies, 19,652 participants, search to Jul 2025)", "cohort": "Pooled biomarker-defined AD cohorts", "n_participants": 19652, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 87.3, "specificity_pct": 85.5, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "Molecular Neurobiology (2026)", "url": "https://doi.org/10.1007/s12035-026-05864-2", "doi": "10.1007/s12035-026-05864-2", "pubmed_id": "42071133", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "modelled (pooled meta-analytic estimate)", "notes": "Amyloid-positivity subgroup recorded (sens 87.3%, spec 85.5%). Overall biomarker-defined AD: sens 85.4% (81.4-88.7), spec 88.0% (85.1-90.6), PLR 7.13, NLR 0.167, DOR 42.7. Clinical AD diagnosis subgroup: sens 72.9%, spec 89.5%. Authors caution about optimized cutoffs and heterogeneity; position p-tau217 as a triage biomarker.", "evidence_strength": "high (systematic review) but heterogeneous" }, { "id": "ptau217-elecsys-hibar2026-impaired", "assay_name": "Roche Elecsys Phospho-Tau (217P) plasma immunoassay (prototype)", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Hibar et al. 2026, Alzheimer's & Dementia", "cohort": "Cognitively impaired from 5 cohorts (n=538: 394 A+, 144 A-)", "n_participants": 538, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 98.98, "specificity_pct": 29.17, "auc": 0.878, "ppv_pct": null, "npv_pct": 92.51, "cutoff_value": 0.189, "cutoff_units": "pg/mL (rule-out cutoff; negative if below)", "year": 2026, "publication": "Alzheimer's & Dementia 22(1):e71009", "url": "https://doi.org/10.1002/alz.71009", "doi": "10.1002/alz.71009", "pubmed_id": "41537338", "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured", "notes": "Cognitively impaired: AUC 0.878 (0.840-0.915); at rule-out cutoff <0.189 pg/mL sensitivity 98.98%, specificity 29.17%, NPV 92.51%. Note this AUC is lower than most academic p-tau217 reports. Five cohorts incl. A4, SKYLINE, AIBL, CREAD/CREAD2 (trial screening populations). Roche-authored. Rule-out cutoff deliberately trades specificity for sensitivity. FDA clearance K261686 (2026-08-19) applies to the commercial assay; this study used the prototype.", "evidence_strength": "moderate-high (large, but industry-run and trial-screening cohorts)" }, { "id": "ptau217-elecsys-hibar2026-unimpaired", "assay_name": "Roche Elecsys Phospho-Tau (217P) plasma immunoassay (prototype)", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Hibar et al. 2026, Alzheimer's & Dementia", "cohort": "Cognitively unimpaired from 5 cohorts (n=1610: 224 A+, 1386 A-)", "n_participants": 1610, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 95.54, "specificity_pct": 50.72, "auc": 0.907, "ppv_pct": null, "npv_pct": 98.6, "cutoff_value": 0.189, "cutoff_units": "pg/mL (rule-out cutoff; negative if below)", "year": 2026, "publication": "Alzheimer's & Dementia 22(1):e71009", "url": "https://doi.org/10.1002/alz.71009", "doi": "10.1002/alz.71009", "pubmed_id": "41537338", "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured", "notes": "Cognitively unimpaired: AUC 0.907 (0.885-0.929); sensitivity 95.54%, specificity 50.72%, NPV 98.60% at <0.189 pg/mL. Five cohorts incl. A4, SKYLINE, AIBL, CREAD/CREAD2 (trial screening populations). Roche-authored. Rule-out cutoff deliberately trades specificity for sensitivity. FDA clearance K261686 (2026-08-19) applies to the commercial assay; this study used the prototype.", "evidence_strength": "moderate-high (large, but industry-run and trial-screening cohorts)" }, { "id": "ptau217-lumipulse-dyer2025-mci", "assay_name": "Fujirebio Lumipulse G pTau217 plasma", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Dyer et al. 2025, Alzheimer's & Dementia: DADM (TIMC-BRAiN)", "cohort": "Tallaght (Dublin) specialist memory service, 148 patients (101 MCI, 47 mild dementia), age 69.4", "n_participants": 148, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.92, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring 17(1):e70080", "url": "https://doi.org/10.1002/dad2.70080", "doi": "10.1002/dad2.70080", "pubmed_id": "39959359", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.92 (0.87-0.97) for CSF-defined Aβ positivity; median p-tau217 >4-fold higher in Aβ+. Two-threshold approach could avoid >half of lumbar punctures.", "evidence_strength": "moderate (single center, small)" }, { "id": "ptau217-ab42-lumipulse-wang2025-clinic", "assay_name": "Fujirebio Lumipulse G plasma p-tau217/Aβ42 ratio", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Wang et al. 2025, Alzheimer's & Dementia (TBRAIN, China)", "cohort": "Clinic cohort, China (n=391)", "n_participants": 391, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.963, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(3):e70038", "url": "https://doi.org/10.1002/alz.70038", "doi": "10.1002/alz.70038", "pubmed_id": "40156286", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Abstract gives AUC 0.963-0.966 across the two cohorts for Aβ-PET (lower bound assigned to clinic; per-cohort assignment not stated in abstract). Tau-PET AUC 0.947-0.974. Ratio outperformed p-tau217 alone, Aβ42/40, p-tau181; equivalent to CSF. Intermediate zone 10.6% (ratio) vs 13.0% (p-tau217 alone).", "evidence_strength": "moderate-high (PET reference, two settings; Chinese population)" }, { "id": "ptau217-ab42-lumipulse-wang2025-community", "assay_name": "Fujirebio Lumipulse G plasma p-tau217/Aβ42 ratio", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Wang et al. 2025, Alzheimer's & Dementia (TBRAIN, China)", "cohort": "Community cohort, China (n=121)", "n_participants": 121, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.963, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(3):e70038", "url": "https://doi.org/10.1002/alz.70038", "doi": "10.1002/alz.70038", "pubmed_id": "40156286", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC range 0.963-0.966 (lower bound recorded). Intermediate-zone fraction 16.5% for ratio vs 31.4% for p-tau217 alone in community, i.e. p-tau217 alone leaves a third of community participants indeterminate. Chinese-population cutoffs established.", "evidence_strength": "moderate-high (PET reference, two settings; Chinese population)" }, { "id": "ptau217-lumipulse-arslan2026-realworld", "assay_name": "Fujirebio Lumipulse G pTau217 plasma (routine clinical lab)", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Arslan et al. 2026, Clinical Chemistry and Laboratory Medicine", "cohort": "Sahlgrenska University Hospital clinical neurochemistry lab, all routine plasma p-tau217 tests Aug 2025-Mar 2026 (n=1,352 measurements; 121 with paired CSF)", "n_participants": 121, "population": "mixed", "comparator": "CSF", "sensitivity_pct": 84.5, "specificity_pct": 87.5, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": 0.22, "cutoff_units": "ng/L (low <0.22; high >0.34; intermediate between)", "year": 2026, "publication": "Clinical Chemistry and Laboratory Medicine (2026)", "url": "https://doi.org/10.1515/cclm-2026-0370", "doi": "10.1515/cclm-2026-0370", "pubmed_id": "42053135", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "REAL-WORLD: positive percent agreement 84.5% (72.6-92.7) and negative percent agreement 87.5% (73.2-95.8) vs CSF Aβ42/40 (recorded as sens/spec). Of 1,352 routine samples, 40.0% low, 16.9% intermediate, 43.1% high probability. Within-batch CV <7.3%. Routine-practice agreement is well below research-cohort AUCs.", "evidence_strength": "moderate (small paired subset, real-world)" }, { "id": "gfap-simoa-pereira2021-biofinder2", "assay_name": "Simoa plasma GFAP (Quanterix)", "analyte": "GFAP", "platform": "Simoa", "sample_type": "plasma", "study_name": "Pereira et al. 2021, Brain", "cohort": "BioFINDER-2: 217 Aβ- CU, 71 Aβ+ CU, 78 Aβ+ CI, 63 Aβ- CI, 75 non-AD neurodegenerative (n=504)", "n_participants": 504, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.76, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2021, "publication": "Brain 144(11):3505-3516", "url": "https://doi.org/10.1093/brain/awab223", "doi": "10.1093/brain/awab223", "pubmed_id": "34259835", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Plasma GFAP predicted Aβ-PET positivity with AUC 0.76 (CSF GFAP 0.69). GFAP tracks amyloid-related astrocytosis, not tau; far below p-tau217 accuracy in the same cohort.", "evidence_strength": "moderate-high" }, { "id": "ptau217-roche-cobas-e801-denkinger2025", "assay_name": "Roche cobas e801 plasma p-tau217 (RUO, fully automated)", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "Denkinger et al. 2025, Alzheimer's & Dementia (AAIC 2025 conference abstract; interim analysis)", "cohort": "WRAP (Wisconsin Registry for Alzheimer's Prevention); interim 2,821 plasma samples of planned 5,574 from 1,982 participants (1,746 CU, 197 CI); 676 with amyloid PET", "n_participants": 676, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.94, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(Suppl 7):e108882 (conference abstract)", "url": "https://doi.org/10.1002/alz.70861_108882", "doi": "10.1002/alz70861_108882", "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": null, "value_type": "measured (interim, conference abstract - not peer-reviewed full paper)", "notes": "AUC 0.94 (0.91-0.96) in full interim sample; 0.92 (0.89-0.96) in cognitively unimpaired. (Commercial Elecsys pTau217 later FDA-cleared K261686, 2026-08-19.) Amyloid PET cutoff 24.1 Centiloids. All four RUO fully automated assays similar in cognitively impaired (AUC >0.94). Industry co-authors (Roche, Beckman Coulter, Siemens).", "evidence_strength": "low-moderate (conference abstract, interim)" }, { "id": "ptau217-siemens-atellica-denkinger2025", "assay_name": "Siemens Healthineers Atellica IM plasma p-tau217 (RUO)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Denkinger et al. 2025, Alzheimer's & Dementia (AAIC 2025 conference abstract; interim analysis)", "cohort": "WRAP (Wisconsin Registry for Alzheimer's Prevention); interim 2,821 plasma samples of planned 5,574 from 1,982 participants (1,746 CU, 197 CI); 676 with amyloid PET", "n_participants": 676, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.92, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(Suppl 7):e108882 (conference abstract)", "url": "https://doi.org/10.1002/alz.70861_108882", "doi": "10.1002/alz70861_108882", "pubmed_id": null, "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured (interim, conference abstract - not peer-reviewed full paper)", "notes": "AUC 0.92 (0.89-0.95). Amyloid PET cutoff 24.1 Centiloids. All four RUO fully automated assays similar in cognitively impaired (AUC >0.94). Industry co-authors (Roche, Beckman Coulter, Siemens).", "evidence_strength": "low-moderate (conference abstract, interim)" }, { "id": "ptau217-beckman-dxi9000-denkinger2025", "assay_name": "Beckman Coulter DxI 9000 Access plasma p-tau217 (RUO)", "analyte": "p-tau217", "platform": "immunoassay", "sample_type": "plasma", "study_name": "Denkinger et al. 2025, Alzheimer's & Dementia (AAIC 2025 conference abstract; interim analysis)", "cohort": "WRAP (Wisconsin Registry for Alzheimer's Prevention); interim 2,821 plasma samples of planned 5,574 from 1,982 participants (1,746 CU, 197 CI); 676 with amyloid PET", "n_participants": 676, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.92, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(Suppl 7):e108882 (conference abstract)", "url": "https://doi.org/10.1002/alz.70861_108882", "doi": "10.1002/alz70861_108882", "pubmed_id": null, "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured (interim, conference abstract - not peer-reviewed full paper)", "notes": "AUC 0.92 (0.89-0.95). Amyloid PET cutoff 24.1 Centiloids. All four RUO fully automated assays similar in cognitively impaired (AUC >0.94). Industry co-authors (Roche, Beckman Coulter, Siemens).", "evidence_strength": "low-moderate (conference abstract, interim)" }, { "id": "ptau217-ab42-lumipulse-denkinger2025", "assay_name": "Fujirebio Lumipulse G1200 plasma p-tau217/Aβ42 ratio", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Denkinger et al. 2025, Alzheimer's & Dementia (AAIC 2025 conference abstract; interim analysis)", "cohort": "WRAP (Wisconsin Registry for Alzheimer's Prevention); interim 2,821 plasma samples of planned 5,574 from 1,982 participants (1,746 CU, 197 CI); 676 with amyloid PET", "n_participants": 676, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.91, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(Suppl 7):e108882 (conference abstract)", "url": "https://doi.org/10.1002/alz.70861_108882", "doi": "10.1002/alz70861_108882", "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": null, "value_type": "measured (interim, conference abstract - not peer-reviewed full paper)", "notes": "AUC 0.91 (0.89-0.94) for ratio vs 0.90 (0.86-0.93) for p-tau217 alone. Note: in this largely cognitively unimpaired community cohort the FDA-cleared ratio scored lowest of the four platforms. Amyloid PET cutoff 24.1 Centiloids. All four RUO fully automated assays similar in cognitively impaired (AUC >0.94). Industry co-authors (Roche, Beckman Coulter, Siemens).", "evidence_strength": "low-moderate (conference abstract, interim)" }, { "id": "ptau217-lumipulse-denkinger2025", "assay_name": "Fujirebio Lumipulse G1200 plasma p-tau217 alone", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Denkinger et al. 2025, Alzheimer's & Dementia (AAIC 2025 conference abstract; interim analysis)", "cohort": "WRAP (Wisconsin Registry for Alzheimer's Prevention); interim 2,821 plasma samples of planned 5,574 from 1,982 participants (1,746 CU, 197 CI); 676 with amyloid PET", "n_participants": 676, "population": "community", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.9, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Alzheimer's & Dementia 21(Suppl 7):e108882 (conference abstract)", "url": "https://doi.org/10.1002/alz.70861_108882", "doi": "10.1002/alz70861_108882", "pubmed_id": null, "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured (interim, conference abstract - not peer-reviewed full paper)", "notes": "AUC 0.90 (0.86-0.93). Amyloid PET cutoff 24.1 Centiloids. All four RUO fully automated assays similar in cognitively impaired (AUC >0.94). Industry co-authors (Roche, Beckman Coulter, Siemens).", "evidence_strength": "low-moderate (conference abstract, interim)" }, { "id": "total-tau-simoa-mattsson2016", "assay_name": "Simoa plasma total tau (Quanterix, research)", "analyte": "total-tau", "platform": "Simoa", "sample_type": "plasma", "study_name": "Mattsson et al. 2016, Neurology", "cohort": "ADNI (179 AD, 195 MCI, 189 controls) and BioFINDER (61 AD, 212 MCI, 174 SCD, 274 controls); n=1284", "n_participants": 1284, "population": "mixed", "comparator": "clinical-diagnosis", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2016, "publication": "Neurology 87(17):1827-1835", "url": "https://doi.org/10.1212/WNL.0000000000003246", "doi": "10.1212/wnl.0000000000003246", "pubmed_id": "27694257", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Plasma total tau: higher in AD dementia but correlations with CSF tau/Aβ42 were weak and inconsistent between cohorts; 'these results do not support plasma tau as an AD biomarker in individual people'. AUC not reported in abstract (null). Included as the reference point that plasma total-tau is not diagnostically useful.", "evidence_strength": "high (large) - negative finding" }, { "id": "ptau217-huang2026-realworld-memory-clinic", "assay_name": "Plasma p-tau217 (platform not stated in abstract)", "analyte": "p-tau217", "platform": "other", "sample_type": "plasma", "study_name": "Huang et al. 2026, The Innovation", "cohort": "Huashan Hospital (Shanghai) memory clinic, 738 consecutive patients with cognitive complaints", "n_participants": 738, "population": "memory-clinic", "comparator": "clinical-diagnosis", "sensitivity_pct": 88, "specificity_pct": 84, "auc": null, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2026, "publication": "The Innovation 7:101272", "url": "https://doi.org/10.1016/j.xinn.2026.101272", "doi": "10.1016/j.xinn.2026.101272", "pubmed_id": "42254957", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Real-world retrospective: sensitivity 0.88, specificity 0.84 for AD (reference = tier-1 amyloid PET or CSF-informed diagnosis). Adding p-tau217 revised 30.2% of diagnoses and raised clinician confidence 65.1% to 79.4%. Assay platform not named in abstract.", "evidence_strength": "moderate (single center, retrospective)" }, { "id": "ptau217-lumipulse-martinezdubarbie2024-preclinical", "assay_name": "Fujirebio Lumipulse G pTau217 plasma", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Martínez-Dubarbie et al. 2024, Journal of Prevention of Alzheimer's Disease (Valdecilla cohort)", "cohort": "Population-based volunteers >55 y without cognitive impairment, Cantabria, Spain (n=209, mean age 64)", "n_participants": 209, "population": "community", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.85, "ppv_pct": null, "npv_pct": null, "cutoff_value": null, "cutoff_units": null, "year": 2024, "publication": "J Prev Alzheimers Dis 11(6):1581-1591", "url": "https://doi.org/10.14283/jpad.2024.152", "doi": "10.14283/jpad.2024.152", "pubmed_id": "39559871", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "PRECLINICAL / cognitively unimpaired: AUC 0.85 for CSF amyloid positivity (p-tau217 + APOE4 as predictors). Median p-tau217 0.26 pg/mL in A+ vs 0.12 in A-. Markedly lower than the 0.94-0.97 AUCs in symptomatic memory-clinic cohorts.", "evidence_strength": "moderate (single center, small)" }, { "id": "ptau217-lumipulse-massons2026-multicenter-realworld", "assay_name": "Fujirebio Lumipulse G pTau217 plasma", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Massons et al. 2026, Annals of Clinical and Translational Neurology", "cohort": "Prospective, 7 memory clinics in Catalonia (only one with prior blood-biomarker experience); consecutive patients with cognitive impairment undergoing CSF testing (n=185)", "n_participants": 185, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.916, "ppv_pct": null, "npv_pct": null, "cutoff_value": 0.146, "cutoff_units": "pg/mL lower cutoff; 0.486 pg/mL upper cutoff (97.5% sens/spec model)", "year": 2026, "publication": "Annals of Clinical and Translational Neurology (2026), e70387", "url": "https://doi.org/10.1002/acn3.70387", "doi": "10.1002/acn3.70387", "pubmed_id": "41968970", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "AUC 0.916 vs CSF Aβ status; single-cutoff accuracy only 84.9%. With strict dual thresholds (97.5% sens/spec), 42.7% of patients fell in the intermediate zone and the remaining 57.3% were classified with 95.3% accuracy. Illustrates the accuracy-vs-indeterminate trade-off in real-world multicenter use.", "evidence_strength": "moderate-high (prospective multicenter real-world)" }, { "id": "ptau217-lumipulse-palmqvist2025-primary-care", "assay_name": "Fujirebio Lumipulse G pTau217 plasma (single predefined cutoff)", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Palmqvist et al. 2025, Nature Medicine", "cohort": "Swedish primary care cohort (n=548)", "n_participants": 548, "population": "primary-care", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": 82, "npv_pct": 88, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Nature Medicine 31:2036-2045", "url": "https://doi.org/10.1038/s41591-025-03622-w", "doi": "10.1038/s41591-025-03622-w", "pubmed_id": "40205199", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "PRIMARY CARE with single cutoff: accuracy 85%, PPV 82%, NPV 88% - notably lower than the 91-92% PPV/NPV of the mass-spec APS2 test in the same setting (Palmqvist 2024). AUC not given separately for primary care in abstract (overall range 0.93-0.96). Reference = AD pathology by abnormal CSF Aβ42:p-tau181. Predefined cutoffs. Total study n=1,767 (4 secondary-care cohorts Malmö/Gothenburg/Barcelona/Brescia + Swedish primary care). Two-cutoff approach raised accuracy to 92-94% while excluding 12-17% intermediate. Accuracy 83% in age >=80. Mass-spec %p-tau217 had higher accuracy in primary care and was unaffected by age.", "evidence_strength": "high (large, multicohort, predefined cutoffs, includes primary care)" }, { "id": "ptau217-lumipulse-palmqvist2025-secondary-care", "assay_name": "Fujirebio Lumipulse G pTau217 plasma (single predefined cutoff)", "analyte": "p-tau217", "platform": "Lumipulse", "sample_type": "plasma", "study_name": "Palmqvist et al. 2025, Nature Medicine", "cohort": "Four secondary-care cohorts: Malmö (n=337), Gothenburg (n=165), Barcelona (n=487), Brescia (n=230)", "n_participants": 1219, "population": "memory-clinic", "comparator": "CSF", "sensitivity_pct": null, "specificity_pct": null, "auc": 0.93, "ppv_pct": 89, "npv_pct": 77, "cutoff_value": null, "cutoff_units": null, "year": 2025, "publication": "Nature Medicine 31:2036-2045", "url": "https://doi.org/10.1038/s41591-025-03622-w", "doi": "10.1038/s41591-025-03622-w", "pubmed_id": "40205199", "fda_clearance": "research-use-only", "fda_clearance_date": null, "value_type": "measured", "notes": "Secondary care: AUC 0.93-0.96 (lower bound recorded), accuracy 89-91%, PPV 89-95% (lower bound), NPV 77-90% (lower bound recorded). Lower NPV bound reflects high-prevalence memory-clinic setting. Reference = AD pathology by abnormal CSF Aβ42:p-tau181. Predefined cutoffs. Total study n=1,767 (4 secondary-care cohorts Malmö/Gothenburg/Barcelona/Brescia + Swedish primary care). Two-cutoff approach raised accuracy to 92-94% while excluding 12-17% intermediate. Accuracy 83% in age >=80. Mass-spec %p-tau217 had higher accuracy in primary care and was unaffected by age.", "evidence_strength": "high (large, multicohort, predefined cutoffs, includes primary care)" }, { "id": "ptau217-elecsys-roche-fda-k261686-overall", "assay_name": "Roche Elecsys Phospho-Tau (217P) Plasma (pTau217), commercial assay", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "FDA 510(k) Summary K261686 pivotal study RD007230 (retrospective; APPROACH cohort RD006263 + AACI phase III screening samples)", "cohort": "Full analysis population, 958 with amyloid PET (age 55-85, mean 71.1; MMSE 20-30; 24.8% primary care, 75.2% secondary/tertiary); PET prevalence 39.5%", "n_participants": 958, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 93.1, "specificity_pct": 92.0, "auc": null, "ppv_pct": 88.5, "npv_pct": 95.3, "cutoff_value": 0.378, "cutoff_units": "pg/mL: Positive >0.378; Negative <=0.223; Intermediate 0.223-0.378", "year": 2026, "publication": "FDA 510(k) Summary K261686 (Elecsys Phospho-Tau (217P) Plasma), decision 2026-08-19", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf26/K261686.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured (PPV/NPV as reported by FDA; sens/spec DERIVED from FDA 2x2 excluding intermediates)", "notes": "Overall 2x2: Positive 285 PET+/37 PET- (PV 88.5%, 84.9-91.4; 33.6% of results); Intermediate 72/119 (19.9% of results; PV 37.7%); Negative 21/424 (46.5% of results; PV for positivity 4.7% => NPV 95.3%). Derived sens 93.1% (285/306), spec 92.0% (424/461) excluding intermediates. LR+ 11.82, LR- 0.08. Reference = amyloid PET visual read, 6 readers (2 vendors x 3), majority vote; inter-reader PPA only 83.6% (range 44.3-100%), NPA 91.3%. 16 sites US/EU; 91.4% US; 84.7% white. Roche did not report AUC in the summary.", "evidence_strength": "high (regulatory pivotal, large) but retrospective and PPV/NPV prevalence-dependent" }, { "id": "ptau217-elecsys-roche-fda-k261686-primary-care", "assay_name": "Roche Elecsys Phospho-Tau (217P) Plasma (pTau217), commercial assay", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "FDA 510(k) Summary K261686 pivotal study RD007230 (retrospective; APPROACH cohort RD006263 + AACI phase III screening samples)", "cohort": "Primary care subgroup (n=238); PET prevalence 21.4%", "n_participants": 238, "population": "primary-care", "comparator": "amyloid-PET", "sensitivity_pct": 94.7, "specificity_pct": 93.5, "auc": null, "ppv_pct": 78.3, "npv_pct": 98.6, "cutoff_value": 0.378, "cutoff_units": "pg/mL: Positive >0.378; Negative <=0.223; Intermediate 0.223-0.378", "year": 2026, "publication": "FDA 510(k) Summary K261686 (Elecsys Phospho-Tau (217P) Plasma), decision 2026-08-19", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf26/K261686.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured (PPV/NPV as reported by FDA; sens/spec DERIVED from FDA 2x2 excluding intermediates)", "notes": "PRIMARY CARE 2x2: Positive 36 PET+/10 PET- (PPV 78.3%, 66.1-87.0; 19.3% of results); Intermediate 13/34 (19.7%); Negative 2/143 (60.9% of results; NPV 98.6%). Derived sens 94.7% (36/38), spec 93.5% (143/153) excluding intermediates. FDA text: PPV 78.3%, NPA 94.7% at upper cutoff; NPV 98.6% at lower cutoff. Reference = amyloid PET visual read, 6 readers (2 vendors x 3), majority vote; inter-reader PPA only 83.6% (range 44.3-100%), NPA 91.3%. 16 sites US/EU; 91.4% US; 84.7% white. Roche did not report AUC in the summary. FDA-defined single-cutoff agreements: lower cutoff PPA 96.1% (49/51), upper cutoff NPA 94.7% (177/187); 19.7% intermediate.", "evidence_strength": "high (regulatory pivotal, large) but retrospective and PPV/NPV prevalence-dependent" }, { "id": "ptau217-elecsys-roche-fda-k261686-secondary-care", "assay_name": "Roche Elecsys Phospho-Tau (217P) Plasma (pTau217), commercial assay", "analyte": "p-tau217", "platform": "Elecsys", "sample_type": "plasma", "study_name": "FDA 510(k) Summary K261686 pivotal study RD007230 (retrospective; APPROACH cohort RD006263 + AACI phase III screening samples)", "cohort": "Secondary/tertiary care subgroup (n=720); PET prevalence 45.4%", "n_participants": 720, "population": "memory-clinic", "comparator": "amyloid-PET", "sensitivity_pct": 92.9, "specificity_pct": 91.2, "auc": null, "ppv_pct": 90.2, "npv_pct": 93.7, "cutoff_value": 0.378, "cutoff_units": "pg/mL: Positive >0.378; Negative <=0.223; Intermediate 0.223-0.378", "year": 2026, "publication": "FDA 510(k) Summary K261686 (Elecsys Phospho-Tau (217P) Plasma), decision 2026-08-19", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf26/K261686.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured (PPV/NPV as reported by FDA; sens/spec DERIVED from FDA 2x2 excluding intermediates)", "notes": "SECONDARY/TERTIARY 2x2: Positive 249/27 (PPV 90.2%, 86.5-93.0; 38.3% of results); Intermediate 59/85 (20.0%); Negative 19/281 (41.7%; NPV 93.7%). Derived sens 92.9% (249/268), spec 91.2% (281/308) excluding intermediates. Reference = amyloid PET visual read, 6 readers (2 vendors x 3), majority vote; inter-reader PPA only 83.6% (range 44.3-100%), NPA 91.3%. 16 sites US/EU; 91.4% US; 84.7% white. Roche did not report AUC in the summary. FDA-defined: lower cutoff PPA 94.2%, upper cutoff NPA 93.1%; 20.0% intermediate.", "evidence_strength": "high (regulatory pivotal, large) but retrospective and PPV/NPV prevalence-dependent" }, { "id": "aps2-c2n-precivityad2-fda-k253240-pet-subset", "assay_name": "C2N PrecivityAD2 (APS2), FDA-cleared IVD version", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "FDA 510(k) Summary K253240, Table 53.25 (amyloid PET visual read comparator subset)", "cohort": "Subset of pooled validation cohort with amyloid PET visual read as reference (n=209; prevalence 45.9%)", "n_participants": 209, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": 91.8, "specificity_pct": 92.7, "auc": null, "ppv_pct": 90.5, "npv_pct": 93.7, "cutoff_value": 66.5, "cutoff_units": "APS2 score: Positive >66.5; Negative <27.5; Likely Positive 27.5-66.5", "year": 2026, "publication": "FDA 510(k) Summary K253240 (PrecivityAD2 Test)", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf25/K253240.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured (PPV/NPV as reported; sens/spec DERIVED from FDA 2x2 excluding Likely Positive)", "notes": "Against PET alone the numbers are lower than the pooled headline: Positive 67 PET+/7 PET- (PPV 90.5%, 81.7-95.3); Likely Positive 23/17 (PV 57.5%; 19.1% of results); Negative 6/89 (PV 6.3% => NPV 93.7%). Derived sens 91.8% (67/73), spec 92.7% (89/96). Compare CSF-comparator subset (n=933): PPV 99.1%, NPV 93.0%, Likely Positive PV 82.3%.", "evidence_strength": "moderate (small PET subset)" }, { "id": "aps2-c2n-precivityad2-fda-k253240-scd-subgroup", "assay_name": "C2N PrecivityAD2 (APS2), FDA-cleared IVD version", "analyte": "p-tau217", "platform": "mass-spec", "sample_type": "plasma", "study_name": "FDA 510(k) Summary K253240, Table 53.27 (subjective cognitive decline subgroup)", "cohort": "SCD subgroup of pooled validation cohort (n=242; amyloid prevalence 24.0%)", "n_participants": 242, "population": "mixed", "comparator": "amyloid-PET", "sensitivity_pct": null, "specificity_pct": null, "auc": null, "ppv_pct": 90.3, "npv_pct": 96.0, "cutoff_value": 66.5, "cutoff_units": "APS2 score: Positive >66.5; Negative <27.5; Likely Positive 27.5-66.5", "year": 2026, "publication": "FDA 510(k) Summary K253240 (PrecivityAD2 Test)", "url": "https://www.accessdata.fda.gov/cdrh_docs/pdf25/K253240.pdf", "doi": null, "pubmed_id": null, "fda_clearance": "cleared", "fda_clearance_date": "2026-08-19", "value_type": "measured", "notes": "Earliest symptomatic stage: Positive PV 90.3% (28/31; 75.1-96.7), Likely Positive PV 67.6% (23/34), Negative PV 4.0% (7/177) => NPV 96.0%; 14.0% Likely Positive. MCI (n=540, prev 53.9%): PPV 97.9%, NPV 91.4%. Dementia (n=360, prev 70.3%): PPV 98.5%, NPV 91.9%. Reference = PET visual read or CSF (pooled).", "evidence_strength": "moderate (subgroup)" } ]