The third FDA-cleared Alzheimer's blood biomarker test is PrecivityAD2, cleared August 20, 2026 to aid Alzheimer's diagnosis. It is for adults age 40 and older with signs or symptoms of cognitive impairment who are being evaluated for Alzheimer's disease, according to C2N Diagnostics in the company announcement. A blood biomarker test measures proteins in blood linked to disease in the brain. This test uses one blood draw to look for amyloid pathology, a buildup tied to Alzheimer's, without at first needing 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 notice from FDA — Use this primary source to verify the official announcement.
- Read the official guidance from C2N — Use this primary source to verify the official guidance.
Table of Contents
- Who is eligible to discuss it?
- What does the test measure?
- How should patients read the results?
- What questions can you bring to primary care?
Who is eligible to discuss it?
The test is for people with noticed cognitive change, not for routine checks. Examples include ongoing memory loss, confusion, word-finding trouble, or problems with planning and daily tasks.
The clearance extends eligibility to age 40, below the prior 55-year threshold for cleared blood tests, as described by NeurologyLive in its clearance report. That change matters for younger-onset symptoms that still need evaluation. A primary care visit can start with these checks:.
- what symptoms occur, how often, and for how long
- medicines, sleep, mood, thyroid issues, vitamin gaps, and head injury history
- whether family or coworkers have noticed change too
What does the test measure?
The laboratory measures two blood signals with high-resolution mass spectrometry: Aβ42/40 and p-tau217/np-tau217. Aβ refers to amyloid-beta fragments. Tau refers to another protein family involved in Alzheimer's changes. The two results are combined into an Amyloid Probability Score 2.
The score has three levels: negative, positive, or likely positive. A clinician interprets that score alongside history, exams, and cognitive testing. No blood result alone proves Alzheimer's. Other brain disorders, medical illness, and medicines can affect thinking and need separate review.
How should patients read the results?
In 1,142 symptomatic adults compared with amyloid PET or spinal-fluid testing, positive results matched amyloid in 97.6% of cases and negative results matched absence in 93.1% of cases. Likely-positive results occurred in 17.3% of cases and matched amyloid in 77.3% of cases. A positive result raises the chance that amyloid is present.
A negative result lowers that chance. A likely-positive result sits in the middle and often needs more discussion. Useful follow-up questions include whether to repeat testing, seek confirmatory PET or spinal-fluid testing, or get referral to neurology, neuropsychology, or a memory clinic. A written plan helps track next steps, work safety, driving, and support at home.
What questions can you bring to primary care?
Bring questions that link symptoms, test limits, and next care. The test must supplement clinical assessment by professionals experienced in cognitive impairment evaluation, and it is not for screening people without symptoms, according to PatientCare and C2N in the test summary.
Consider asking: Bring a one-page symptom timeline, medicine list, and a family member or friend who knows daily function. Ask what visit will cover results and decisions.
- Do my symptoms make this blood test appropriate for me now?
- What else could explain my symptoms besides Alzheimer's?
- What would negative, positive, or likely-positive mean in my case?
- Would a result change referrals, confirmatory testing, treatment options, or care planning?
- Who will explain the result, how soon, and what records should I bring?
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