Who Should Get a Blood Test for Alzheimer's Disease?

—Artico—Getty Images For decades, the only way to confirm that someone had Alzheimer’s disease was by autopsy after death, when pathologists could confirm amyloid plaques, which are hallmarks of the disease, in the brain.

Doctors now use a combination of factors to diagnose Alzheimer’s, including reports from patients and their caregivers about changes in memory or other cognitive functions, performance on cognitive tests, brain imaging, and tests of spinal fluid.

But some of these measures can be subjective, invasive, expensive, or hard to assess.

Enter the blood tests.

There are now four blood tests cleared by the U.S.

Food and Drug Administration (FDA) to detect the earliest signs of the neurodegenerative disease: an important advance in helping to diagnose Alzheimer’s in more people, as well as detecting it earlier in the disease course.

“This is a very exciting time for the field,” says Dr.

Eric Reiman, CEO emeritus and lead researcher at the Banner Alzheimer’s Institute in Phoenix.

“We’re going to start personalizing Alzheimer’s care similar to cancer, where we can inform diagnosis, prognosis, and staging to further inform disease severity.” The two newest blood tests cleared by the U.S.

Food and Drug Administration (FDA) in August make blood tests for Alzheimer's disease more widely available for doctors to prescribe—and in a younger population of people—for the first time.

But that doesn't mean everyone should get one.

Here's what to know about the available blood tests for Alzheimer's disease and when experts recommend taking them.

The first two blood tests for Alzheimer's disease The first blood test for the disease, made by Fujirebio, was cleared by the FDA in May 2025 .

It determines the ratio of two key Alzheimer’s proteins—a form of beta amyloid and a form of tau —which reflects whether amyloid plaques are accumulating in the brain.