The Alzheimer's Association reports the third FDA-cleared Alzheimer's blood biomarker test in 2026 is C2N Diagnostics' PrecivityAD2, cleared on Aug. 20, 2026 clearance announcement. It is the first cleared test for symptomatic adults as young as 40, and a fourth cleared option followed four days later.
A blood biomarker test measures Alzheimer's-related proteins in blood to help assess amyloid pathology. Amyloid pathology means buildup of amyloid plaques linked to Alzheimer's disease. PrecivityAD2 does not replace a clinical exam and does not screen healthy people.
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 C2N’s official study page — Use this page to check the study’s participation requirements.
- Read the official guidance from Alz — Use this primary source to verify the official guidance.
Table of Contents
- What came before PrecivityAD2?
- How does PrecivityAD2 lower the age floor?
- How accurate is it?
- Who is it for — and who is it not for?
- What comes next in primary care?
What came before PrecivityAD2?
Practical Neurology reports the first FDA-cleared blood test was Fujirebio's Lumipulse G pTau217/Beta-Amyloid 1-42 Plasma Ratio in May 2025. It was cleared for adults 55 and older with cognitive impairment. That clearance established the FDA-cleared blood-test category. Being Patient reports the second clearance was Roche's Elecsys pTau181 on Oct.
13, 2025. It was cleared for primary-care evaluation of adults 55 and older with cognitive complaints. Labcorp launched it nationwide in Feb. 2026.
How does PrecivityAD2 lower the age floor?
NeurologyLive reports PrecivityAD2 uses high-resolution mass spectrometry to measure plasma AB42/40 plus p-tau217/np-tau217 test details. The results combine into an Amyloid Probability Score 2. The score returns negative, positive, and likely-positive categories.
C2N Diagnostics says the practical change is earlier triage for patients ages 40 to 54. Those patients previously fell below age cutoffs. A blood result can now guide referral, workup, and trial-enrichment decisions.
How accurate is it?
NeurologyLive reports study results in 1,142 symptomatic adults compared with amyloid PET or spinal-fluid testing accuracy data. Positive predictive value was 97.6 percent and negative predictive value was 93.1 percent. Predictive value means how often the blood result matched the PET or spinal-fluid result.
The intermediate likely-positive group included 17.3 percent of patients. Positive predictive value in that group was 77.3 percent. That group needs clinical judgment and often confirmatory testing.
Who is it for — and who is it not for?
C2N Diagnostics says PrecivityAD2 is cleared only for patients with signs or symptoms of cognitive impairment. It must supplement standard clinical workup.
It is neither population screening nor a stand-alone diagnosis. Check fit before asking your doctor:.
- age 40 or older with memory, thinking, or functional symptoms
- evaluation by a clinician who can do a standard workup
- not for routine screening without symptoms
- not a final diagnosis without clinical context and follow-up testing
What comes next in primary care?
The near-term change is faster triage and faster amyloid confirmation for adults 40 to 54. Primary care doctors can use a result to prioritize neurology referral, complete workup, and discuss trial eligibility. A positive or likely-positive result still points toward PET or spinal-fluid confirmation. Four days later the options grew again.
Assisted Living Leader reports FDA cleared Roche and Eli Lilly's single-biomarker Elecsys Phospho-Tau 217P Plasma test on Aug. 24, 2026 for symptomatic adults 55 and older clearance report. That clearance brought cleared options to four. Ask your doctor which test your clinic uses and what confirmatory step follows your score category.
You Might Also Like
- The Third FDA-Cleared Alzheimer’s Blood Biomarker Test in 2026: Accuracy, Limits, and Evidence Gaps for Primary Care Patients
- PrecivityAD2 as an Adjunct to a 2026 Alzheimer’s Assessment: What Changed and What Comes Next for Primary Care Patients
- Early Dementia Detection Across Care Settings in the 2026 NIA Report: What Changed and What Comes Next for Spouses and Partners
