The FDA cleared the PrecivityAD2 Alzheimer's blood test on Aug. 20, 2026 for adults age 40 and older with signs or symptoms of cognitive impairment.
PrecivityAD2 is a single-draw blood test that estimates amyloid buildup risk to aid a doctor's evaluation, not to diagnose alone. For primary care patients, the change is practical. Memory concerns in midlife can now trigger a regulated blood test during a routine workup, rather than starting with a brain scan or spinal tap.
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:
- Read the official guidance from Washu — Use this primary source to verify the official guidance.
- Read the official guidance from Neurologylive — Use this primary source to verify the official guidance.
Table of Contents
- What one blood draw measures
- Who qualifies — and who does not
- How accurate was it in testing?
- What should you do at your visit?
What one blood draw measures
The test uses high-resolution mass spectrometry to measure plasma amyloid-beta 42/40 ratio and percent phosphorylated tau 217. Those results combine into a proprietary Amyloid Probability Score 2. Amyloid-beta and phosphorylated tau are blood markers linked to Alzheimer's brain changes.
The test was developed and validated by St. Louis-based C2N Diagnostics using technology invented at Washington University School of Medicine in St. Louis, according to WashU Medicine in its clearance announcement.
Who qualifies — and who does not
The clearance covers symptomatic adults age 40 and older, making it the first FDA-cleared Alzheimer's blood test for patients that young, NeurologyLive reports in its clearance report. It is cleared only as an aid alongside standard clinical workup by clinicians experienced in cognitive impairment. The FDA did not clear the test as a stand-alone diagnosis or asymptomatic screening test, according to AJMC in its September analysis.
- Ask about it if you have noticed memory loss, confusion, word-finding trouble, or behavior change.
- A family member's concern about your thinking also fits the symptomatic group.
- Do not seek it as routine screening without symptoms.
- Do not use the score alone as a diagnosis.
How accurate was it in testing?
In a 1,142-person validation cohort compared with amyloid PET or spinal-fluid testing, the test showed 97.6 percent positive predictive value and 93.1 percent negative predictive value. About 17.3 percent of results fell in a likely-positive middle group, with 77.3 percent predictive value. A middle score means amyloid is possible but less certain.
In a separate 1,310-patient study across 165 physicians, primary-care diagnostic accuracy rose from 65 percent to 93 percent after doctors saw PrecivityAD2 results. That result matched dementia specialists at about 90 to 94 percent. The gain matters because most memory concerns first reach a primary-care office.
What should you do at your visit?
Clearance adds a third regulated option to a category with no FDA-cleared blood tests just over a year earlier, extending testing below prior age-55 thresholds. For patients, it offers a less-invasive alternative to PET scans or lumbar puncture that may speed diagnosis and earlier treatment decisions, Practical Neurology notes in its practice summary.
C2N's laboratory test remains available while the FDA-cleared version was expected later in 2026. Ask your clinic which version it orders and how results will be explained.
- Bring specific examples with dates: missed bills, repeated questions, getting lost.
- List medicines, sleep problems, hearing loss, depression, and family history.
- Ask what workup will accompany the blood test, such as exam, labs, and cognitive testing.
- Ask what a negative, positive, or middle score would change next.
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