C2N Diagnostics wins FDA clearance for PrecivityAD2 as Alzheimer’s blood testing race widens

C2N Diagnostics, LLC has secured U.S. Food and Drug Administration clearance for PrecivityAD2, a blood-based test designed to aid assessment of Alzheimer’s disease pathology in adults aged 40 and older who show signs or symptoms of cognitive impairment. The privately held diagnostics company says PrecivityAD2 is the first FDA-cleared Alzheimer’s blood test available for symptomatic patients as young as 40 and the first such cleared test based on high-resolution mass spectrometry combined with a multiple-analyte algorithm. The August 20, 2026 milestone brings regulatory validation to technology C2N has already been offering in laboratory-developed-test form and comes as blood biomarkers rapidly move from research tools toward routine Alzheimer’s diagnostic workflows. The commercial significance lies not simply in replacing one test with another, but in reducing dependence on costly amyloid positron emission tomography scans and invasive cerebrospinal-fluid procedures for appropriate patients.

PrecivityAD2 is not intended to screen healthy people for future Alzheimer’s risk and should not be interpreted as an independent diagnosis of dementia. The test is intended for patients with cognitive signs or symptoms and must be used alongside clinical assessment and other relevant information. That distinction becomes increasingly important as disease-modifying Alzheimer’s treatments make accurate identification of amyloid pathology more clinically consequential.

How does the PrecivityAD2 Alzheimer’s blood test work?

PrecivityAD2 measures blood biomarkers associated with amyloid pathology using high-resolution mass spectrometry. The underlying methodology quantifies the ratio of amyloid-beta 42 to amyloid-beta 40 and the proportion of phosphorylated tau217 relative to non-phosphorylated tau217. These measurements are combined through C2N’s algorithm to produce an Amyloid Probability Score 2, or APS2, that indicates the likelihood that amyloid pathology is present in the brain.

That approach differs technically from several competing blood tests that use immunoassay platforms. Mass spectrometry can provide highly quantitative protein measurements but requires specialized laboratory infrastructure and analytical expertise. C2N’s commercial model therefore centers on centralized high-complexity testing rather than a simple point-of-care assay that could immediately be run in every physician office.

Independent validation research published before the FDA clearance reported sensitivity of approximately 90% and specificity of approximately 92% for identifying brain beta-amyloid pathology. Predictive performance varies with disease prevalence because positive and negative predictive values change depending on the population being tested, which is another reason PrecivityAD2 needs to be used in clinically appropriate symptomatic patients rather than broad population screening.

Why does the age-40 indication matter in Alzheimer’s diagnostics?

The FDA-cleared population begins at age 40, younger than some previously cleared Alzheimer’s blood-test populations. C2N and the Alzheimer’s Drug Discovery Foundation describe PrecivityAD2 as the first cleared Alzheimer’s blood test available to symptomatic adults at that age. This potentially gives neurologists and other specialists another regulated diagnostic option when evaluating relatively young patients with unexplained cognitive impairment.

Early-onset Alzheimer’s disease remains relatively uncommon, and cognitive symptoms in younger adults can result from many other neurological, psychiatric, metabolic or medical conditions. The test therefore does not mean Alzheimer’s testing should be applied indiscriminately from age 40. Its relevance is that when symptoms and clinical context justify biomarker evaluation, a blood test may now offer a less burdensome first step than lumbar puncture or specialized PET imaging.

How does PrecivityAD2 compare with PET scans and cerebrospinal-fluid testing?

Amyloid PET imaging can directly visualize amyloid accumulation in the brain, while cerebrospinal-fluid assays measure biomarkers using fluid obtained by lumbar puncture. Both approaches are established but carry practical limitations. PET requires specialized imaging infrastructure and can be expensive, while lumbar puncture is invasive and may be less acceptable to some patients.

A routine blood draw is substantially easier to integrate into neurology and potentially primary-care pathways. Washington University School of Medicine said studies of PrecivityAD2 have demonstrated more than 90% accuracy for detecting amyloid pathology and that performance can be comparable with more invasive reference methods in appropriate patient populations. The clinical advantage is therefore less about claiming superior accuracy to every existing method and more about making biomarker assessment easier to obtain.

Blood testing may also function as a triage tool. A clinician could potentially use a high-quality blood biomarker result to identify patients who are more or less likely to require confirmatory imaging or cerebrospinal-fluid testing, reducing unnecessary procedures. How far that model goes will depend on professional guidelines, reimbursement policies and physicians’ confidence in specific assays.

Why are Alzheimer’s blood diagnostics suddenly becoming a major commercial market?

The emergence of anti-amyloid therapies has increased the value of knowing whether a symptomatic patient actually has amyloid pathology. Disease-modifying treatments are designed for defined stages of Alzheimer’s disease and carry their own treatment risks and monitoring requirements, making inaccurate diagnosis potentially costly both medically and financially. Diagnostic bottlenecks therefore become more important as more patients seek assessment for treatment eligibility.

The FDA-cleared Alzheimer’s blood-test category has also expanded quickly. The Alzheimer’s Drug Discovery Foundation noted that the United States had no FDA-cleared Alzheimer’s blood tests little more than a year earlier and now has three. C2N is therefore entering a nascent but increasingly competitive regulated market rather than enjoying an uncontested category.

PrecivityAD2’s differentiation rests on mass spectrometry, its combination of amyloid and tau biomarkers, its younger indicated age threshold and C2N’s long history in Alzheimer’s protein measurement. Competitors can differentiate through automated laboratory platforms, turnaround time, pricing, installed instrument bases or relationships with large diagnostic laboratories, so technical accuracy alone may not decide market leadership.

Does FDA clearance immediately replace C2N’s existing laboratory-developed test?

Not yet. C2N says the PrecivityAD2 test currently available to clinicians remains its laboratory-developed test offered under Clinical Laboratory Improvement Amendments regulations. The newly FDA-cleared version is expected to become commercially available in the coming months. That creates a transition period in which the PrecivityAD2 brand exists in both its existing LDT form and an FDA-cleared version preparing for launch.

This distinction matters for providers and payers because regulatory status can influence coverage policies, institutional adoption and procurement decisions. C2N has already expanded access internationally and has gained coverage from Anthem for its existing PrecivityAD2 service, giving the company some commercial groundwork before launch of the cleared assay. FDA clearance could make discussions with additional payers and health systems easier, but reimbursement will still be determined separately from regulatory authorization.

What is the biggest business opportunity for C2N Diagnostics?

The largest opportunity is changing the diagnostic funnel itself. If reliable blood biomarkers become the routine entry point for symptomatic Alzheimer’s assessment, the volume of tests could be far larger than the number of PET scans or cerebrospinal-fluid procedures currently performed. That would make blood diagnostics a central infrastructure layer supporting neurology, memory clinics and potentially parts of primary care.

C2N’s challenge is that this opportunity is attracting increasingly well-capitalized diagnostics companies. Scale will require rapid turnaround, payer coverage, clinician education and convincing evidence that PrecivityAD2 improves clinical decision-making rather than simply adding another biomarker result. FDA clearance gives C2N a much stronger regulatory position, but the next race is commercial: which Alzheimer’s blood tests become embedded in everyday diagnostic pathways as treatment and diagnosis move earlier in the disease course.