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Analytical Validation and Performance of a Blood-Based P-tau217 Diagnostic Test for Alzheimer Disease
Abel A, Chambers A, Fill J, Reiske H, Lu M, Morris A, Faya P, Beck RC et al.. The journal of applied laboratory medicine, 2025-05-01
Topic: Amyloid, tau and blood-test diagnosis
Background Blood-based biomarkers, especially P-tau217, have been gaining interest as diagnostic tools to measure Alzheimer disease (AD) pathology. Methods We developed a plasma P-tau217 chemiluminescent immunoassay using 4G10E2 and IBA493 as antibodies, a synthetic tau peptide as calibrator, and the Quanterix SP-X imager. Analytical validation performed in a College of American Pathologists-accredited CLIA laboratory involved multiple kit lots, operators, timepoints, and imagers. Florbetapir positron emission tomography was used to quantify amyloid for clinical validation. Results Precision across 80 runs was ≤20% CV using 23 patient-derived samples ranging from 0.09 U/mL to 3.35 U/mL. No significant lot-to-lot differences were observed. There was no interference from purified tau (2N4R) or lipemia, but hemolysis greater than 2 + was not acceptable. Functional analytical sensitivity (lower limit of quantitation) was 0.08 U/mL. Linearity studies support the use of a standard 1:2 plasma dilution. Samples demonstrated stability at 7 freeze/thaw cycles, with room temperature and refrigerated stability established for up to 72 hours. The final analytical measurement range was 0.08 to 2.81 U/mL. The calibration curve maintained ≤20% CV for raw signal intensity and 80% to 120% relative error for back-fitted concentration using a log-log power regression. Initial clinical assessment using plasma samples from 1091 individuals screened in TRAILBLAZER-ALZ 2 demonstrated an area under the curve of 91.6% (95% CI 0.90-0.94) with brain amyloid as the comparator. Positive and negative predictive value was >90% and >85%, respectively. Conclusions Through analytical validation, this assay demonstrated robust performance across multiple lots, operators, and instruments and could be used as a tool for diagnosing AD.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Abel, A., Chambers, A., Fill, J., Reiske, H., Lu, M., Morris, A., et al. (2025). Analytical Validation and Performance of a Blood-Based P-tau217 Diagnostic Test for Alzheimer Disease. The journal of applied laboratory medicine. https://doi.org/10.1093/jalm/jfae155
Vancouver
Abel A, Chambers A, Fill J, Reiske H, Lu M, Morris A, et al. Analytical Validation and Performance of a Blood-Based P-tau217 Diagnostic Test for Alzheimer Disease. The journal of applied laboratory medicine. 2025. doi:10.1093/jalm/jfae155. PMID: 39836199.
BibTeX
@article{abel2025-39836199,
author = {Abel, A. and Chambers, A. and Fill, J. and Reiske, H. and Lu, M. and Morris, A. and Faya, P. and Beck, R. C. and others},
title = {{Analytical Validation and Performance of a Blood-Based P-tau217 Diagnostic Test for Alzheimer Disease}},
journal = {The journal of applied laboratory medicine},
year = {2025},
doi = {10.1093/jalm/jfae155},
pmid = {39836199},
url = {https://doi.org/10.1093/jalm/jfae155}
}
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Key findings
- Results Precision across 80 runs was ≤20% CV using 23 patient-derived samples ranging from 0.09 U/mL to 3.35 U/mL.
- No significant lot-to-lot differences were observed.
- Samples demonstrated stability at 7 freeze/thaw cycles, with room temperature and refrigerated stability established for up to 72 hours.
- Initial clinical assessment using plasma samples from 1091 individuals screened in TRAILBLAZER-ALZ 2 demonstrated an area under the curve of 91.6% (95% CI 0.90-0.94) with brain amyloid as the comparator.
- Conclusions Through analytical validation, this assay demonstrated robust performance across multiple lots, operators, and instruments and could be used as a tool for diagnosing AD.
Why it matters
This paper reports the analytical validation of a blood test for P-tau217, including precision, stability, and an initial clinical assessment against brain amyloid. It is a test-development study and does not itself treat, cure, or prevent Alzheimer's disease.
New to this subject? Start with our plain-English guide: Blood tests & biomarkers →
Study details
- Participants1,091
- Effect size91.6%
- Evidence strengthLow
How this study scored 43/100
Published in a peer-reviewed journal. Scored zero for study design and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (The journal of applied laboratory medicine) |
| Journal's citation record | 0 / 4 | The Journal of Applied Laboratory Medicine: journal h-index 44 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 3 / 4 | 1,091 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 2 / 7 | Cited 9 times (OpenAlex, 2026-10-10) |
| Citations per year | 2 / 5 | 3.0 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 3 / 6 | Cited 4.9× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 1 / 4 | Cited 9 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Michael E. Hodsdon: h-index 30 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Eli Lilly (United States): institution h-index 744 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 39836199) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 43 / 100 | — |
What each of these 20 components measures, and what this score is not →
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