The third FDA-cleared Alzheimer's blood biomarker test is C2N Diagnostics' PrecivityAD2, cleared on Aug. 20, 2026. The Alzheimer's Association reported that clearance as the third of its kind in the Association announcement.
For memory clinic patients, it works as an aid that helps rule amyloid pathology in or out, while intermediate scores often need further testing. An Alzheimer's blood biomarker test measures proteins in blood to estimate whether amyloid plaques are present in the brain. It joins two earlier regulated options, giving memory clinics three FDA-cleared blood tests by August 2026. Clinical Lab Products records list the earlier clearances as Fujirebio Lumipulse in May 2025 and Roche Elecsys in October 2025.
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.
- Check eligibility on Roche’s official study page — Use this page to check the study’s participation requirements.
Table of Contents
- What does the test measure?
- How well does it predict amyloid?
- Who is it for, and what are its limits?
- How does it change a memory clinic visit?
What does the test measure?
PrecivityAD2 measures the plasma Aβ42/40 ratio and percent p-tau217. The method uses immunoprecipitation plus liquid chromatography-tandem mass spectrometry, according to the FDA decision summary described in the FDA decision summary. The two results combine into an Amyloid Probability Score 2 from 0 to 100.
A higher score signals a higher likelihood of brain amyloid pathology. A low score points away from amyloid as the cause of symptoms. A middle-range score falls in a less certain band that calls for clinical judgment.
How well does it predict amyloid?
In a 1,142-patient symptomatic validation cohort, positive results matched amyloid PET or spinal-fluid results 97.6% of the time. Negative results matched negative PET or spinal-fluid results 93.1% of the time, as reported by NeurologyLive in the NeurologyLive report. The comparison standard was amyloid PET or cerebrospinal fluid testing.
About 17.3% of patients fell in an intermediate "likely positive" band. In that subgroup, 77.3% were amyloid-positive, so the result did not settle the question alone. Those patients often need PET or spinal-fluid confirmation before treatment decisions.
Who is it for, and what are its limits?
C2N states the test is cleared for adults age 40 and older with signs or symptoms of cognitive impairment who are being evaluated for Alzheimer's or other cognitive decline, described in the C2N announcement. That is the youngest cleared age group among the three tests.
It is not cleared for screening people without symptoms. The test works only as an aid alongside that workup, not as a stand-alone diagnosis. The Alzheimer's Association 2025 guideline limits specialty-care blood-biomarker use to cognitively impaired patients and advises confirmation after lower-specificity triage results.
- Age 40 or older with memory or thinking symptoms
- Evaluation already underway for Alzheimer's or other cognitive decline
- Testing ordered alongside standard clinical workup
How does it change a memory clinic visit?
The practical gain is a routine blood draw that can sort amyloid likelihood sooner. A clear positive or negative result can speed referral, trial screening, and treatment-eligibility review. Roche's investor update describes the same role for blood p-tau testing in primary and specialty care.
Ask whether your clinic offers an FDA-cleared blood biomarker test and which confirmation path it uses. Bring a symptom timeline, a medication list, and copies of prior brain scans or lab work. Plan for PET or spinal-fluid testing if your score lands in the intermediate band.
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