FDA cleared PrecivityAD2, a blood test for Alzheimer's-related brain amyloid, in August 2026 for adults 40 and older with cognitive symptoms. For memory clinic patients, it offers a validated aid to evaluation, but an intermediate score band and need for clinical follow-up leave real uncertainty. C2N Diagnostics said in BioSpace the Aug.
20, 2026 clearance covers symptomatic adults needing workup for Alzheimer's or other decline FDA clearance announcement. FDA labeling says the test is not for screening without symptoms and not a stand-alone diagnosis. It must accompany clinical assessment by professionals experienced in cognitive-impairment evaluation.
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 Biospace — Use this primary source to verify the official guidance.
- Check eligibility on Bondtrials’s official study page — Use this page to check the study’s participation requirements.
Table of Contents
- Who qualifies for testing?
- How does the score work?
- Where does uncertainty remain?
- What should you ask at the visit?
Who qualifies for testing?
The clearance applies to adults aged 40 and older with signs or symptoms of cognitive impairment. They must be undergoing evaluation for Alzheimer's disease or other cognitive decline. FixFirst Health notes this age-40 start is lower than the age-55 floor for the Fujirebio and Roche cleared tests.
Eligibility is narrow and clinical: The Alzheimer's Association 2025 guidance, as reported by Healio, also focuses on objectively impaired patients seen in specialty care. That match matters because memory clinics already combine history, exams, and cognitive testing. The blood result fits into that workup, not in place of it.
- age 40 or older
- ongoing memory, thinking, or daily-function changes
- active evaluation for Alzheimer's or other decline
- ordering and interpretation by a clinician experienced in cognitive impairment
- no routine screening when symptoms are absent
How does the score work?
The test measures two blood markers: the Aβ42/Aβ40 ratio, meaning the balance of two amyloid protein fragments, and percent p-tau217, meaning a modified tau protein linked to amyloid buildup. C2N Diagnostics said in its United Kingdom announcement the lab uses high-resolution mass spectrometry, a method that identifies molecules by weight, then combines the results into an Amyloid Probability Score called APS2 from 0 to 100 global partnership announcement. In a 1,142-person symptomatic validation group, results were checked against amyloid PET scans or spinal-fluid biomarkers. C2N Diagnostics said through Business Wire that a Positive result was correct 97.6% of the time and a Negative result was correct 93.1% of the time Japan partnership announcement.
A Positive result therefore strongly favors brain amyloid, while a Negative result strongly favors its absence. The Association guidance treats high-accuracy blood tests as triage or confirmation against PET or spinal-fluid standards. In practice, a clear Positive or Negative can reduce the need for a scan or spinal tap. An unclear result still points toward those reference tests.
Where does uncertainty remain?
About 17.3% of results fall in an intermediate band often called likely positive. Bond Health, citing refreshed FDA data, reports only about 77.3% of that subgroup were amyloid-positive Bond Health analysis. That means roughly three in four were positive and one in four were not. For these patients, the blood test does not settle the question.
Other limits are fixed in labeling. The test cannot screen people without symptoms. It cannot diagnose Alzheimer's alone. Clinical judgment, other causes of impairment, and sometimes PET or spinal-fluid testing remain necessary. Patients with mixed conditions, new medications, or recent medical illness need especially careful interpretation.
What should you ask at the visit?
Access and payment remain variable. Retirement Living reports the FDA-cleared kit was expected later in 2026, while a clinician-ordered laboratory version remained available through C2N's certified laboratory. Insurance coverage varied and Medicare had no national policy.
Bring a clear history and ask direct questions: Ask whether a Positive result needs confirmation before starting a therapy tied to amyloid. Ask whether an intermediate result means scheduling PET or spinal-fluid testing now. Bring a family member, a symptom timeline, and a current medication list to that visit.
- what symptoms, timeline, and test results support blood testing for me
- whether my APS2 result is Positive, Negative, or intermediate and what comes next
- how the result changes treatment, trial eligibility, safety planning, or follow-up timing
- which lab will run the test, what it costs, and what insurance will pay
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