The Food and Drug Administration cleared C2N Diagnostics' PrecivityAD2 blood test on August 20, 2026, for adults 40 and older who show signs of cognitive impairment and are being evaluated for Alzheimer's disease.
It is the first Alzheimer's blood test the agency has cleared for patients as young as 40.
The test is meant to be used alongside a full clinical workup, not as a screening tool or a standalone diagnosis.
A doctor still weighs memory tests, medical history and a neurological exam before deciding what a result means for the patient.
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Until now, checking for the amyloid plaques linked to Alzheimer's usually required a positron emission tomography (PET) brain scan or a spinal tap to sample cerebrospinal fluid.
Both are more invasive, more expensive and harder to access than a routine blood draw.
What the test actually measures
PrecivityAD2 uses high-resolution mass spectrometry to quantify specific proteins in plasma: the Aβ42/40 amyloid ratio and the p-tau217/np-tau217 tau ratio.
Those two ratios are combined into an Amyloid Probability Score 2, or APS2, on a scale of 0 to 100.
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The score reflects the likelihood that amyloid plaques, one of the hallmark brain changes of Alzheimer's, are present.
Amyloid buildup is not the same thing as dementia, and a positive result does not mean a patient has Alzheimer's.
It means the biology consistent with the disease is likely there, and a doctor can use that information alongside other findings.
How well it performs
Clearance was based on a study of 1,142 adults, where PrecivityAD2 was compared against amyloid PET imaging or cerebrospinal fluid testing.
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In that trial, positive results had a 97.6% positive predictive value and negative results had a 93.1% negative predictive value, according to C2N Diagnostics.
Results in the middle range, flagged as likely positive, occurred in 17.3% of participants and carried a 77.3% positive predictive value.
The underlying science came out of Washington University in St. Louis, where neurologists Randall J. Bateman and David M. Holtzman developed the mass-spectrometry methods and co-founded C2N in 2007 to commercialize them.
What it means for patients
PrecivityAD2 is the third blood-based biomarker test the FDA has cleared for Alzheimer's, and the first available to symptomatic adults in their 40s.
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The company has said the newly cleared version will roll out later in 2026 through licensed clinicians.
Coverage will follow. Eligible Anthem Blue Cross and Blue Shield members are set to be the first in the United States to receive insurance coverage under a medical policy for PrecivityAD2 starting October 1, 2026.
The test is ordered by a healthcare provider, not requested directly by patients from a lab.
Adults 40 and older who are noticing memory problems, or whose family has noticed changes, can raise the option with their doctor as part of a cognitive evaluation.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.