FDA clears the first blood test for Alzheimer’s disease

On May 16, 2025 the FDA cleared the first blood test to help diagnose Alzheimer’s disease: the Fujirebio Lumipulse plasma p-tau217 / amyloid-beta 42 ratio, for adults 55 and older who already have cognitive symptoms. A blood draw now does work that used to need a PET scan or a spinal tap.

The number that makes this real: p-tau217-based tests classify brain amyloid status with roughly 90 to 95% accuracy. In the clearance data, the test matched amyloid PET or spinal-fluid results about 92% of the time for positives and 97% for negatives, which puts a simple blood test on par with far more invasive ones.

Why this matters for a carrier: it makes amyloid testing cheaper and far less invasive, so getting clarity during a symptomatic workup gets easier. But read the result carefully. A positive reflects Alzheimer’s biology, not a diagnosis on its own and not your destiny, and the test is meant to support a clinical evaluation, not replace it.

The honest caveat, and the most important one for carriers: this was cleared for adults who have symptoms, not as a screen for healthy people. Testing an asymptomatic carrier is a different decision with real psychological stakes and no current treatment to change.

We cover what these tests can and cannot tell you in our deep dive on blood-based biomarkers for Alzheimer’s. Primary source: FDA, 2025. This is education, not medical advice.