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Clinical validation of the PrecivityAD2 blood test: A mass spectrometry-based test with algorithm combining %p-tau217 and Aβ42/40 ratio to identify presence of brain amyloid
Kristopher M. Kirmess, Stephanie Eastwood, Traci L. Wente-Roth, Faith Irvin, Mary S. Holubasch, Venky Venkatesh, Ilana Fogelman, Mark Monane, Lucy Hanna, Gil D. Rabinovici, Barry A. Siegel, Rachel A. Whitmer, Charles Apgar, Randall J. Bateman, David M. Holtzman, Michael Irizarry, David Verbel, Pallavi Sachdev, Satoshi Ito, John Contois, Kevin E. Yarasheski, Joel B. Braunstein, Philip B. Verghese, Tim West. Alzheimer's & Dementia, 2024-05
Topic: Amyloid, tau and blood-test diagnosis
This study validated PrecivityAD2, a mass-spectrometry blood test made by C2N Diagnostics that combines two markers (%p-tau217 and the amyloid-beta 42/40 ratio) into a single 'Amyloid Probability Score 2.' In 583 people being evaluated for cognitive problems, the test agreed with amyloid PET scan results about 88% of the time, with performance holding up across different ages, sexes, and ethnic groups.
Key findings
- 583 participants with suspected Alzheimer's; 53% were amyloid-PET positive
- AUC-ROC of 0.94 for %p-tau217-based algorithm vs PET
- Overall agreement with amyloid PET of about 88%
- Performance consistent across ethnicity, sex, age, and APOE4 status
Why it matters
A blood test can reliably detect amyloid protein in the brain, which is associated with Alzheimer's pathology, by measuring %p-tau217 and the amyloid-beta 42/40 ratio. This validation study in 583 people shows the blood test agrees with brain imaging about 88% of the time, but does not demonstrate whether using this test to guide treatment decisions improves outcomes.
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Study details
- Study designcross-sectional
- Participants583
- Effect sizeAUC-ROC 0.94; overall percent agreement with amyloid PET ~88%
- Evidence strengthHigh
Limitations
Cross-sectional validation against PET as the reference standard; several authors are C2N Diagnostics employees/consultants, the test's maker.
How this study scored 65/100
Published in a leading specialty journal, and it is a snapshot of people at one point in time. Scored zero for randomised / blinded and indexed in PubMed because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, still being cited, senior author's track record, institution's track record, multi-centre collaboration and free to read, so those were left out: it earned 40 of the 62 points we could judge it on, which is 65 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Alzheimer's & Dementia) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 4 / 12 | A snapshot of people at one point in time |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2024 — within 3 year(s) of the newest study here |
| Sample size | 2 / 4 | 583 participants |
| Effect reported | 3 / 3 | Effect reported with a statistic (interval, p-value, ratio or similar) |
| 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 | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 0 / 2 | No PubMed ID and no DOI — scores zero (not stated in the record — scored 0) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 40 / 62 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 40 of the 62 points we could judge it on is 65 out of 100. |
| Total | 65 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. This record has no DOI, so the citation leaves it out. Volume, issue and page numbers are not held in the record. The record names 24 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
APA 7th
Kirmess, K. M., Eastwood, S., Wente-Roth, T. L., Irvin, F., Holubasch, M. S., Venkatesh, V., et al. (2024). Clinical validation of the PrecivityAD2 blood test: A mass spectrometry-based test with algorithm combining %p-tau217 and Aβ42/40 ratio to identify presence of brain amyloid. Alzheimer's & Dementia.
Vancouver
Kirmess KM, Eastwood S, Wente-Roth TL, Irvin F, Holubasch MS, Venkatesh V, et al. Clinical validation of the PrecivityAD2 blood test: A mass spectrometry-based test with algorithm combining %p-tau217 and Aβ42/40 ratio to identify presence of brain amyloid. Alzheimer's & Dementia. 2024.
BibTeX
@article{kirmess2024-1b1b5bc0,
author = {Kirmess, Kristopher M. and Eastwood, Stephanie and Wente-Roth, Traci L. and Irvin, Faith and Holubasch, Mary S. and Venkatesh, Venky and Fogelman, Ilana and Monane, Mark and Hanna, Lucy and Rabinovici, Gil D. and Siegel, Barry A. and Whitmer, Rachel A. and Apgar, Charles and Bateman, Randall J. and Holtzman, David M. and Irizarry, Michael and Verbel, David and Sachdev, Pallavi and Ito, Satoshi and Contois, John and Yarasheski, Kevin E. and Braunstein, Joel B. and Verghese, Philip B. and West, Tim},
title = {{Clinical validation of the PrecivityAD2 blood test: A mass spectrometry-based test with algorithm combining \%p-tau217 and Aβ42/40 ratio to identify presence of brain amyloid}},
journal = {Alzheimer's \& Dementia},
year = {2024}
}
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