PrecivityAD2 is a blood test cleared to help detect amyloid buildup in adults age 40 and older with cognitive symptoms, used alongside clinical assessment. It is not a screening test or a stand-alone diagnosis for Alzheimer's disease. Amyloid buildup means abnormal protein deposits linked to Alzheimer's disease.
According to the clearance announcement from C2N Diagnostics via BusinessWire, the FDA cleared the test on Aug. 20, 2026 for symptomatic adults being evaluated for Alzheimer's. Your primary care doctor still leads the evaluation.
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 adjunct mean for your visit?
- How does the test measure risk?
- How reliable is the result?
- What should you ask and do next?
What does adjunct mean for your visit?
Adjunct means the blood result adds to an exam, history, and cognitive testing. As described in the report from Practical Neurology, the test is cleared to help detect amyloid pathology, not to screen healthy people or diagnose alone.
In practice, your doctor evaluates symptoms first and orders the test only when Alzheimer's is a real possibility. A result then helps guide referrals, counseling, and whether further testing makes sense. It does not replace judgment about other causes of memory change.
How does the test measure risk?
The test uses immunoprecipitation plus LC-MS/MS to measure four blood markers. The FDA decision summary describes plasma Aβ42, Aβ40, p-tau217 and np-tau217, combined as Aβ42/40 and percent p-tau217 ratios.
Those ratios become an Amyloid Probability Score 2 from 0 to 100. A higher score means amyloid pathology is more likely. A lower score means it is less likely.
How reliable is the result?
In a 1,142-person validation group with cognitive symptoms, the test matched amyloid PET or spinal fluid testing well. According to the summary from NeurologyLive, positive results were right 97.6% of the time and negative results were right 93.1% of the time. Results held across age groups and 12 other conditions, NeurologyLive reports. Those included chronic kidney disease, atrial fibrillation, and diabetes.
That stability matters because these conditions are common in primary care and often distort lab tests. About 17.3% of patients fell in a middle band called likely positive, NeurologyLive reports. In that band, positives were right 77.3% of the time. A middle result needs clinical judgment and may need spinal fluid or PET confirmation.
What should you ask and do next?
Bring specific examples of memory, thinking, or daily-task changes, with dates. Ask whether blood testing fits your symptoms, what other causes must be ruled out, and what each possible result would change.
The Alzheimer's Association guideline from July 29, 2025 says certain blood tests may triage suspected Alzheimer's, with positives confirmed by spinal fluid or PET. Practical Neurology notes the FDA-cleared kit version was expected later in 2026, while C2N's CLIA laboratory test remained orderable, so ask your clinic which channel it uses.
- Ask if you meet the symptomatic adult use described in the clearance
- Ask how a negative, positive, or middle score would affect referral
- Ask whether spinal fluid or amyloid PET confirmation is available locally
- Ask how medicines, kidney function, and other conditions affect follow-up
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