Most people have had the moment. You walk into a room and forget why you came in. For many families, those small lapses eventually turn into a quiet worry nobody wants to say out loud.
That worry has been hard to settle. Confirming Alzheimer's early has long required a PET brain scan or a spinal tap. Both are costly, and both are only offered at specialist centers.
The FDA has now cleared the first blood test that can flag the same brain changes with a simple draw. The test, called Lumipulse, was approved in May 2025 for adults aged 55 and older who are already showing memory or thinking symptoms.
It is not a screening test for healthy people without symptoms.
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How the test reads brain changes from a blood sample
The test, made by the diagnostics company Fujirebio, measures two proteins in blood plasma. One is a form of tau called p-tau217. The other is a fragment known as beta-amyloid 1-42.
Both are hallmarks of Alzheimer's disease. Amyloid builds up as sticky plaques between brain cells years before symptoms appear. Tau twists into tangles inside neurons and disrupts how they communicate.
The ratio of the two proteins flags whether brain amyloid is likely present. An FDA review tested the method on 499 blood samples.
NeurologyLive reports that nearly 92 percent of positive results agreed with a PET scan or spinal fluid test. Negative results agreed about 97 percent of the time.
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Why the price tag changes who gets diagnosed
The access barrier has largely been money and geography. A PET brain scan carries a national average cost of about $4,637 for an uninsured patient, the American Journal of Managed Care reports.
Medicare covers 80 percent after the deductible, but the scans are only offered at specialist centers to begin with.
The blood draw itself is routine lab work and far cheaper to run. Earlier diagnosis also matters because the newest Alzheimer's drugs, which aim to clear amyloid from the brain, work best when brain damage is still limited.
Doctors caution the test should not stand alone. Results need to be read alongside cognitive testing, family history, and a neurological exam. False positives could lead to a wrong diagnosis and unneeded treatment.
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If memory changes have started to affect daily life, talk to your doctor about whether a blood test for Alzheimer's biomarkers is appropriate. The current clearance is for people aged 55 and older who already have symptoms.
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This article is made and published by Aksel Kryhlmand, who may have used AI in the preparation.