Do blood tests really help diagnose Alzheimer’s disease?

In May 2022, the FDA approved a blood test to help diagnose Alzheimer’s disease. The test looks for amyloid-beta protein, a marker of Alzheimer’s. The blood test is quite accurate, compared with positron emission tomography (PET) brain scans, which are more expensive and complicated. More blood tests, including some that look for tau protein (another marker of Alzheimer’s), also are under development. Other tests used to diagnose Alzheimer’s include computed tomography (CT), magnetic resonance imaging (MRI), and a spinal tap.