C2N Diagnostics announced in its August 2026 clearance announcement that PrecivityAD2 is FDA-cleared to help assess amyloid buildup linked to Alzheimer's in symptomatic adults. NeurologyLive reported in its August 2026 coverage that the test covers adults 40 and older, reaching younger-onset patients under 65.
C2N Diagnostics states in its clearance notice that the test is not for screening without symptoms and cannot diagnose Alzheimer's alone. Use requires clinical history, cognitive testing, and other workup. This briefing explains eligibility, scores, accuracy, and next steps.
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
- Who qualifies at 40 or older?
- How does the score work?
- How accurate is it in the clinic?
- What should you do with a result?
Who qualifies at 40 or older?
NeurologyLive reports the indication is adults 40 and older with signs of cognitive impairment. The Alzheimer's Association describes younger-onset Alzheimer's as disease in people under 65, many in their 40s and 50s.
You qualify for discussion only if you have ongoing cognitive symptoms and are undergoing evaluation. The test does not apply to preventive checks or family-risk screening while symptoms are absent.
How does the score work?
NeurologyLive describes high-resolution mass spectrometry to measure plasma Aβ42/40 and percent p-tau217 ratios. Those results combine into an Amyloid Probability Score 2. The score sorts results into negative, likely-positive, and positive bands.
Negative suggests amyloid pathology is unlikely; positive suggests it is likely. Likely-positive is an intermediate call that needs extra testing. Your clinician reads the band with your history and test scores.
How accurate is it in the clinic?
NeurologyLive reports in its updated coverage that a 1,142-person symptomatic cohort was checked against amyloid PET or spinal fluid. In that study reported by NeurologyLive, positive results showed 97.6% positive predictive value and negative results showed 93.1% negative predictive value.
NeurologyLive's updated coverage notes about 17.3% of results fell in the intermediate likely-positive band. Only 77.3% of those intermediate results were amyloid-positive, so those patients need confirmatory PET or spinal-fluid testing.
What should you do with a result?
The Alzheimer's Association's 2025 guideline endorses triage use only for impaired specialty-care patients when tests reach at least 90% sensitivity and 75% specificity. That frame fits memory-clinic evaluation.
Ask your memory clinic whether the blood result changes your need for PET or spinal-fluid testing. Bring prior test scores and a timeline of symptoms to that visit. Keep the blood result with your full cognitive workup for treatment decisions.
- Confirm you had cognitive symptoms at testing.
- Ask which score band you fell in.
- Ask if confirmatory testing is advised.
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