On August 20, 2026, the FDA cleared PrecivityAD2, a blood test that measures Alzheimer's-linked proteins to aid evaluation in people with cognitive symptoms. For primary care patients, the established gain is higher accuracy alongside standard clinical workup, while middle-range results still need follow-up testing. According to the C2N Diagnostics announcement, clearance covers use together with standard clinical evaluation, not as a solo diagnosis. The test is for adults age 40 and older who already show signs of cognitive impairment, as reported by the Patient Care Online report.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Official resources:
- Check eligibility on Washu’s official study page — Use this page to check the study’s participation requirements.
- Read the official guidance from C2N — Use this primary source to verify the official guidance.
Table of Contents
- Who qualifies for testing?
- How does the test work?
- How accurate is a clear result?
- What still needs follow-up?
Who qualifies for testing?
The cleared use is narrow. It covers adults 40 and older with current cognitive signs or symptoms. The clinician must be evaluating Alzheimer's or other cognitive decline.
The test is not for screening people without symptoms. WashU Medicine reports current guidance advises against testing in that group. A primary care visit should first document history, exam, and basic workup.
- age 40 or older
- signs or symptoms of cognitive impairment now
- evaluation for Alzheimer's or other decline
- test used with standard workup, not alone
How does the test work?
The lab uses high-resolution mass spectrometry on a blood sample. It measures the A-beta 42/40 ratio, the balance between two amyloid fragments, and percent p-tau217, the share of a phosphorylated tau form tied to Alzheimer's. Patient Care Online reports the two results combine into the Amyloid Probability Score 2, scaled from 0 to 100.
A Negative score points away from brain amyloid. A Positive score points toward it. A Likely Positive score sits between and needs more evaluation.
How accurate is a clear result?
The validation enrolled 1,142 people and compared results with amyloid PET visual read or spinal-fluid markers. A Positive result showed 97.6% positive predictive value.
A Negative result showed 93.1% negative predictive value, according to C2N via the Boston Life Sciences Times report. Clearance research reported primary care accuracy rose from about 65% with workup alone to 93% with PrecivityAD2, as covered by AJMC. Medical News Today notes this is the first symptomatic-use clearance down to age 40, below prior clearances at 55 and older.
What still needs follow-up?
About 17.3% of validation participants fell into Likely Positive. In that group predictive value was only 77.3%, so doctors need added workup or confirmatory PET or spinal-fluid testing, according to BrightFocus Foundation summary in the BrightFocus Foundation summary.
For primary care, use the result to guide referral and next tests, not to set the diagnosis alone. Bring a symptom timeline, current drugs, and a family member who knows daily changes. Ask whether PET or spinal-fluid testing is warranted after a Likely Positive result.
You Might Also Like
- FDA’s 2026 PrecivityAD2 Alzheimer’s Blood Test Clearance: Result Interpretation Questions for Primary Care Patients
- The Third FDA-Cleared Alzheimer’s Blood Biomarker Test in 2026: Result Interpretation Questions for Primary Care Patients
- PrecivityAD2 as an Adjunct to a 2026 Alzheimer’s Assessment: Result Interpretation Questions for Primary Care Patients
