Memory slips happen to everyone. Forgetting a name, walking into a room and forgetting why. Most of the time it means nothing, but when symptoms show up early, families can wait years for real answers.
That wait may get shorter. On August 20, 2026, the FDA cleared a new blood test called PrecivityAD2. It is meant for adults as young as 40 who show signs of cognitive impairment.
The test looks for the amyloid plaques that define Alzheimer's disease, according to C2N Diagnostics, the St. Louis company that makes it.
A positive result does not mean a person has Alzheimer's. It means the sticky brain plaques that build up in the disease are likely present, measured through a single blood draw.
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The maker says the test is meant to work alongside a full clinical work-up, not replace it. It is not a screening test for healthy adults.
How the test spots the plaques
PrecivityAD2 measures two protein ratios in the blood. One compares two forms of amyloid, the protein that clumps into plaques. The other tracks p-tau217, a form of the tau protein tied to Alzheimer's brain damage.
The two ratios feed into a single score from 0 to 100 that reflects the likelihood of amyloid pathology, the company says.
When the test came back positive in the data submitted to the FDA, it correctly ruled in amyloid plaques about 98 percent of the time. When negative, it correctly ruled the plaques out roughly 93 percent of the time.
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Why finding the plaques early matters
Amyloid plaques can start building years, sometimes decades, before memory symptoms show up. Confirming them used to require a spinal tap or a PET brain scan, both invasive and costly.
A blood test lowers that barrier and could give younger patients answers when their symptoms would otherwise be brushed off as stress or overwork.
The Alzheimer's Association welcomed the clearance and pointed out that younger-onset Alzheimer's, which strikes people under 65, is a real condition clinicians often miss.
What the test can and cannot do
The FDA cleared PrecivityAD2 only for adults who already show signs of cognitive impairment. It is not approved as a screen for healthy people who simply want to know their risk.
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And no blood test can, on its own, diagnose Alzheimer's. Doctors are expected to read the result alongside medical history, cognitive testing and a neurological exam.
Anyone worried about memory changes should raise it with their doctor, who can refer them for a fuller evaluation.
PrecivityAD2 is the third Alzheimer's blood test the FDA has cleared, following an earlier blood test the agency cleared in 2025 that opened up the field.
For now, the test is available through C2N's own clinical laboratory. The FDA-cleared version is expected to reach US clinicians later in 2026, the company said.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.