The FDA announced on August 20 that it has cleared C2N Diagnostics’ PrecivityAD2 blood test for use in adults as young as 40 who are experiencing signs of cognitive impairment, expanding its authorized use below the 50-and-older threshold the test previously carried. The clearance was announced not by C2N itself but by the Alzheimer’s Drug Discovery Foundation (ADDF), a nonprofit that has funded C2N’s research for nearly two decades; C2N is privately held and does not trade under a stock ticker, so this article draws on independently published data about the test’s actual performance rather than relying solely on the funder’s framing of the milestone.

What the Test Measures and How Well It Works

PrecivityAD2 is a blood test that measures two biomarkers, an amyloid beta ratio and a tau protein ratio, and combines them into a score that estimates the likelihood a patient has amyloid plaques in the brain, one of the hallmark features of Alzheimer’s disease. Historically, confirming that pathology required a PET brain scan or a spinal tap to test cerebrospinal fluid, both more invasive and expensive than a blood draw. A peer-reviewed study published in the journal npj Dementia, independent of C2N’s own marketing materials, found the test performed with 91% accuracy, 90% sensitivity, and 92% specificity against amyloid PET imaging in people with cognitive impairment, and a separate large study published in JAMA reported similar performance in both primary care and specialized memory care settings. Those figures come from clinical studies, not from ADDF’s press release, and give a more concrete picture of the test’s reliability than the funding-history narrative alone. Even a well-validated test like this one is meant to be used alongside a clinical evaluation rather than as a standalone diagnosis, and false positives and false negatives remain possible, as they do with any diagnostic test.

The Funder’s Perspective

ADDF CEO Isobel Coleman said the clearance shows how quickly the field has moved, noting that just over a year ago there were no FDA-cleared Alzheimer’s blood tests and now there are three, and credited the ADDF’s early, sustained investment in C2N with helping move the technology from lab research to clinical use. The ADDF says its relationship with C2N goes back to 2008, when it provided seed funding that helped develop PrecivityAD, an earlier test in the same product family, and that it has continued supporting the company since, including a $7 million investment through its Diagnostics Accelerator program. Those figures are the ADDF’s own accounting of its funding history rather than independently audited numbers, though the underlying FDA clearance itself is a matter of public record.

A Second Funded Test Also Cleared

The ADDF also pointed to the FDA’s separate clearance of Fujirebio’s Lumipulse blood test, another diagnostic the foundation has funded, as evidence that its early-stage investment strategy is producing results across more than one company. Fujirebio operates as part of H.U. Group Holdings, a company listed on the Tokyo Stock Exchange, giving that particular comparison at least one point of public-market relevance even though PrecivityAD2’s maker, C2N, remains private.

What ADDF Says This Means for Trials

ADDF interim Chief Science Officer Laura Nisenbaum said tests like PrecivityAD2 do more than diagnose Alzheimer’s; she said they can also help identify appropriate candidates for clinical trials and confirm whether an experimental drug is engaging its intended target, and cited a statistic that 83% of active Alzheimer’s trials now incorporate a biomarker. That figure was stated in her quote without a named source or citation in the release, so it should be read as an ADDF-reported figure rather than an independently confirmed one.

Part of a Broader Shift Toward Precision Medicine

The ADDF frames this clearance as part of a broader shift in Alzheimer’s care toward precision medicine, the idea of matching specific treatments to specific patients based on their individual biology, similar to practices already common in cancer treatment. The foundation says it currently funds 47 active diagnostics programs across seven different research pathways, including next-generation biomarkers for tau and other disease processes, though none of the specifics of those other programs were detailed in this release.

About C2N and the Broader Market

C2N Diagnostics, based in St. Louis, has been building out its Precivity test line for several years; alongside PrecivityAD2, the company also offers the original PrecivityAD test for patients 55 and older and a separate Precivity-ApoE test that looks at a different genetic risk factor. The broader shift toward blood-based Alzheimer’s diagnostics has been driven in part by the arrival of newer disease-modifying drugs that work best when started early, which has increased demand for a diagnostic pathway that is faster and less invasive than PET scans or spinal taps.

What’s Next

Founded in 1998 by Leonard A. and Ronald S. Lauder, the ADDF describes itself as the only public charity solely focused on funding Alzheimer’s drug development, and says it has awarded nearly $400 million across 792 programs in 21 countries to date. Those figures describe the foundation’s own philanthropic track record rather than anything specific to this clearance. This article covers an FDA regulatory action and is not medical advice; patients and caregivers with questions about Alzheimer’s testing should consult a qualified healthcare professional.

Sources

FDA Clearance of C2N Diagnostics’ PrecivityAD2 Blood Test Advances Precision Medicine for Alzheimer’s, Building on Groundwork Laid by Early ADDF Investment, PRNewswire, August 20, 2026.

Dementia: independent validation of the PrecivityAD2 blood test’s diagnostic performance,

Editorial Disclosure

This article is based on a press release issued by the Alzheimer’s Drug Discovery Foundation on August 20, 2026, distributed via PRNewswire, with clinical performance data drawn from an independently published, peer-reviewed study cited above rather than from the press release itself. C2N Diagnostics is a privately held company and does not trade under a stock ticker; no securities are discussed in this article. BioTech Stocks Daily was not compensated for this coverage. Statistics regarding the ADDF’s funding history and the proportion of clinical trials using biomarkers are the foundation’s own reported figures. This article is for informational and educational purposes only and is not medical advice. Consult a qualified healthcare professional for medical guidance. See our full DISCLAIMER.