The third FDA-cleared Alzheimer's blood biomarker test is C2N's PrecivityAD2, cleared Aug. 20, 2026, according to the Alzheimer's Association in its clearance announcement. It is a blood measure of proteins tied to brain amyloid, and patients compare options by age range, method, and follow-up.
PrecivityAD2 is for adults with signs of cognitive impairment, not for routine screening. For memory-clinic patients, it offers amyloid assessment from one blood draw. That avoids a PET scan or spinal tap at the first step, and AJMC reporting notes it may speed diagnosis and treatment choices.
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 guidance from Alz — Use this primary source to verify the official guidance.
- Read the official guidance from C2N — Use this primary source to verify the official guidance.
Table of Contents
- Who can use PrecivityAD2?
- What does the test measure?
- How do the three cleared tests compare?
- What happens after the blood draw?
Who can use PrecivityAD2?
PrecivityAD2 is indicated for adults age 40 and older with signs or symptoms of cognitive impairment. C2N Diagnostics describes it as the first cleared blood test available to symptomatic patients in their 40s.
That matters for younger patients with memory concerns and a family history. A clinician still confirms symptoms through history, exam, and cognitive testing. Bring examples of forgetfulness, work problems, and dates when changes began.
What does the test measure?
The test uses high-resolution mass spectrometry, as described by C2N in its test announcement. It measures plasma Aβ42/40 and p-tau217/non-p-tau217 ratios. It combines them into an Amyloid Probability Score 2.
The score estimates the likelihood of brain amyloid. A higher score points toward amyloid pathology. An uncertain score does not settle the question.
How do the three cleared tests compare?
Each test detects amyloid-related signals in blood, but access and design differ. Age is often the first filter at referral.
Ask your clinic which test it runs and why. Ask what sample it needs and how long results take. Ask whether an uncertain result leads to PET or spinal-fluid testing.
- Fujirebio Lumipulse G pTau217/β-Amyloid 1-42 plasma ratio, cleared in May 2025 for patients 55 and older, was the first FDA-cleared blood test for amyloid pathology, according to Fujirebio in its product description
- Roche Elecsys pTau217, cleared Aug. 24, 2026 for people 55 and older with cognitive complaints, is a single-biomarker test for rule-in and rule-out, according to Roche in its clearance update
- C2N PrecivityAD2, for symptomatic adults 40 and older, combines two ratios into one probability score
What happens after the blood draw?
The blood test is an aid, not a standalone diagnosis. AJMC reporting on the clearance states it is used alongside history, exam, and cognitive testing. It is not for screening people without symptoms.
A clear positive or negative result guides the next visit. An uncertain result usually means PET imaging or cerebrospinal-fluid testing. Bring a symptom timeline, medication list, and a family member to make that follow-up faster.
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