*♦️ FDA Clears First Blood Test Used in Diagnosing Alzheimer’s Disease* The U.S. Food and Drug Administration cleared for marketing the first in vitro diagnostic device that tests blood to aid in diagnosing Alzheimer’s disease. The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio is for the early detection of amyloid plaques associated with Alzheimer’s disease in adult patients, aged 55 years and older, exhibiting signs and symptoms of the disease.