The FDA cleared PrecivityAD2, a blood test made by C2N Diagnostics, on August 20, 2026, for adults 40 and older who have signs of cognitive impairment and are being evaluated for Alzheimer's disease or related decline, according to C2N's announcement. For someone with mild cognitive impairment (MCI) — a stage where thinking or memory problems are noticeable but don't yet stop daily life — this clearance adds a third blood-based option for narrowing down whether amyloid plaque, a protein buildup linked to Alzheimer's, is likely present. The test doesn't diagnose Alzheimer's by itself. It gives a doctor evidence to weigh alongside a clinical exam, cognitive testing, and sometimes imaging, as part of working out what's causing a patient's symptoms.
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 original report from News Medical — Use this primary source to review the complete report.
- Read the official guidance from Healthday — Use this primary source to verify the official guidance.
Table of Contents
- What PrecivityAD2 Actually Measures
- How It Compares to the Other FDA-Cleared Blood Tests
- Why This Matters for People With MCI Specifically
- What a Result Actually Tells You — and Its Limits
- When the Test Will Actually Be Available
- Frequently Asked Questions
What PrecivityAD2 Actually Measures
PrecivityAD2 uses high-resolution mass spectrometry — a lab technique that identifies and weighs molecules with precision — rather than the immunoassay method used by competing tests, to measure amyloid-related proteins in blood plasma, according to News-Medical. The result is reported as an amyloid probability score, not a simple positive-or-negative answer. In the clinical validation study behind the clearance, which involved 1,142 participants, the test matched amyloid PET or spinal fluid (CSF) testing results — the existing reference standards — with a 97.6% positive predictive value and a 93.1% negative predictive value, according to HealthDay.
Those numbers describe how reliably a positive or negative blood result lines up with what a PET scan or spinal tap would have shown in that same study population. The FDA states that PrecivityAD2 is meant to support, not replace, a full clinical workup, and it is not cleared for screening people who have no symptoms, according to HealthDay / Medical Economics. That means a healthy 45-year-old without memory complaints can't request this test as a preventive check — it's built for people already showing symptoms and already in a diagnostic evaluation.
How It Compares to the Other FDA-Cleared Blood Tests
PrecivityAD2 is the third FDA-cleared blood-based Alzheimer's biomarker test. The first was Fujirebio's Lumipulse G pTau217/β-amyloid1-42 ratio test, cleared in May 2025 for adults 55 and older, which showed 91.7%/97.3% concordance with PET or CSF testing. The second was Roche/Lilly's Elecsys pTau217 test, also cleared for adults 55 and older, according to BrightFocus Foundation. The practical difference for someone with MCI is age eligibility and method.
Lumipulse and Elecsys both use immunoassay technology and both start at age 55. PrecivityAD2's cleared age floor is 40, according to Healio. That gap matters directly for people experiencing cognitive symptoms in their 40s or early 50s, who previously had no FDA-cleared blood test available to them at all and would have gone straight to PET scanning or a lumbar puncture. Here's how the three compare at a glance: None of the three is a standalone diagnosis. All three are meant to sit inside a specialist's evaluation, not replace it.
- **PrecivityAD2** — mass spectrometry, ages 40+, 97.6% PPV / 93.1% NPV against PET/CSF
- **Lumipulse G (Fujirebio)** — immunoassay, ages 55+, 91.7%/97.3% concordance with PET/CSF
- **Elecsys pTau217 (Roche/Lilly)** — immunoassay, ages 55+
Why This Matters for People With MCI Specifically
For patients with mild cognitive impairment, the main value of any of these tests is narrowing down whether amyloid pathology is a likely contributor to their symptoms — without first going through a PET scan or a spinal tap. The Alzheimer's Association describes PrecivityAD2 as adding a third validated option that can reduce reliance on costlier, less accessible PET scans or CSF testing during this kind of diagnostic workup, according to the Alzheimer's Association. That reduced reliance matters because PET scans and lumbar punctures are harder to access than a blood draw — they typically require specialized imaging centers or a procedure performed by a specialist, and both cost more out of pocket in many cases.
A blood test that a primary care doctor or neurologist can order as a first step can shorten the time between a patient first reporting symptoms and getting a clearer picture of what's driving them. For a patient under 55 with MCI, PrecivityAD2 is now the only one of the three cleared tests they're eligible for by age. That's a meaningful shift for earlier-onset cases, where amyloid testing previously meant going straight to PET or CSF regardless of symptom severity.
What a Result Actually Tells You — and Its Limits
Results aren't always a clean positive or negative. In the validation study, about 17.3% of participants fell into an intermediate "likely positive" category, where the positive predictive value dropped to 77.3% — notably lower than the 97.6% seen in the overall cohort, according to HealthDay.
That's a meaningfully higher chance of a false signal. If a patient with MCI gets this intermediate result, it's worth discussing directly with the ordering specialist rather than treating it as a final answer. An indeterminate result is exactly the kind of result where a follow-up conversation about additional testing — PET, CSF, or simply monitoring over time — is appropriate, rather than accepting the blood result alone as confirmation either way.
When the Test Will Actually Be Available
C2N says the FDA-cleared version of PrecivityAD2 will become commercially available later in 2026. In the meantime, the company's existing CLIA-validated laboratory version — a lab-developed test regulated under separate federal lab-certification rules rather than FDA device clearance — continues to be offered through C2N's own lab, according to Healio. A patient asking a doctor about this test today should expect to be offered the existing lab-developed version first, with the newly cleared version arriving on a rolling basis as C2N scales up commercial availability through the rest of 2026.
Frequently Asked Questions
Can someone without symptoms request PrecivityAD2 as a preventive screening test?
No. The FDA cleared it only for adults 40 and older who already show signs or symptoms of cognitive impairment and are undergoing evaluation, not for screening people with no symptoms.
Does a positive PrecivityAD2 result mean a person definitely has Alzheimer's?
No. It reports an amyloid probability result meant to support a specialist's broader evaluation, not to serve as a standalone diagnosis.
Why would someone in their 40s with MCI consider PrecivityAD2 over the other blood tests?
Lumipulse and Elecsys are both cleared only for ages 55 and up, so PrecivityAD2 is currently the only FDA-cleared blood test available to younger patients with cognitive symptoms.
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