PrecivityAD2 is an FDA-cleared blood test that helps clinicians evaluate signs of cognitive impairment in adults aged 40 and older, used alongside standard exams and workup rather than alone. For family caregivers, the news means a 2026 Alzheimer's assessment may include a simpler first biomarker step before brain scans or spinal fluid tests. The test does not screen healthy people and does not diagnose Alzheimer's by itself. It gives the evaluating clinician one more clue about amyloid buildup, a hallmark brain change linked to Alzheimer's disease.
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.
Table of Contents
- What does the test measure?
- Who is it for?
- How well does it rule Alzheimer's in or out?
- What should caregivers do next?
What does the test measure?
PrecivityAD2 analyzes a single blood draw with high-resolution mass spectrometry. According to Washington University School of Medicine in its summary of the clearance, the test measures plasma Aβ42/40 plus p-tau217/np-tau217 and combines them into an Amyloid Probability Score 2.
That score estimates the likelihood of brain amyloid seen on PET scans or spinal fluid tests. The clinician reads it together with memory testing, history, exams, and often imaging.
Who is it for?
The clearance covers adults aged 40 and older who already show signs of cognitive impairment and are being evaluated for Alzheimer's or other decline, according to C2N Diagnostics in the FDA clearance announcement. It is indicated only as an adjunct to standard clinical workup.
It is not intended for routine screening or as a stand-alone diagnosis. The Alzheimer's Association guideline directs specialists to use blood biomarkers only after objective impairment is found.
How well does it rule Alzheimer's in or out?
In 1,142 symptomatic adults, scores showed 97.6% positive and 93.1% negative predictive value versus amyloid PET or spinal fluid, according to NeurologyLive in its report on the validation data. That pattern supports both rule-in and rule-out use when the result is clearly negative or positive.
Performance held across age groups and 12 comorbidities that often confound blood tests, including kidney disease, atrial fibrillation, and diabetes. For caregivers, steady performance matters because many older adults live with those conditions.
What should caregivers do next?
About 17.3% of patients received an intermediate "likely positive" result with only 77.3% positive predictive value, so those results remain uncertain without follow-up. Lower-accuracy positives usually need confirmation with PET or spinal fluid testing under current specialist guidance.
Bring notes about daily changes, medications, and medical history to the evaluation visit. Ask the evaluating clinician: For caregivers, the practical effect is a less invasive first biomarker step that can clarify next tests and referrals when reviewed with the evaluating clinician.
- Is a biomarker test appropriate after cognitive testing?
- What does this score change about referrals, confirmatory testing, or trial eligibility?
- What is the plan if the result falls in the uncertain range?
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