Photo by Testalize.me on Unsplash (illustrative)
On 16 May 2025, the US Food and Drug Administration cleared the first blood test to aid in diagnosing Alzheimer's disease. The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio test, made by Fujirebio Diagnostics, is for adults aged 55 and older who already show signs of memory or thinking decline.
Key facts
The test measures two proteins in plasma, pTau217 and beta-amyloid 1-42, and uses their ratio to predict whether amyloid plaques are present in the brain.
In a study of 499 samples from cognitively impaired adults, 91.7% of positive results matched plaques confirmed by PET scan or spinal fluid testing.
97.3% of negative results matched a negative PET scan or spinal fluid test.
Fewer than 20% of patients received an indeterminate result.
Why it matters
Until now, confirming amyloid plaques usually meant a PET scan or a lumbar puncture, which many clinics cannot offer. A simple blood draw could help more people with memory problems get an earlier, clearer answer, at a time when nearly 7 million Americans live with Alzheimer's.
Worth noting
The FDA says the test is not for screening people without symptoms and must not be used alone to make a diagnosis or choose treatment. Researchers note biomarker levels can vary between ethnic groups, so wider validation is still needed.