Several blood tests are now FDA-cleared to help clinicians evaluate adults who already have memory or thinking problems, by looking for signs of the brain changes linked to Alzheimer’s disease. A result is one piece of the evaluation, not a diagnosis on its own, and these tests are not meant for people without symptoms.

Published 15 September 2026 · sources checked 15 September 2026 · pending clinical review by Kanwar Partap Singh Gill, MD

What the tests measure

Alzheimer’s disease involves a buildup of two proteins in the brain, amyloid-beta and tau. Certain forms of these proteins can be measured in blood. Higher levels suggest that amyloid buildup, one hallmark of Alzheimer’s, is more likely.

What is FDA-cleared

As of late August 2026, four blood-based tests had been cleared by FDA. They include tests intended to help rule out Alzheimer’s-related changes in primary care, and a newer test that can help rule in or rule out those changes in primary and specialty care. The cleared uses involve people who have symptoms; for at least some of the tests, clearance is for adults aged 55 and older.

How to understand a result

Negative: Alzheimer’s-related amyloid changes are unlikely. Your clinician will still look for other causes of your symptoms.
Positive: amyloid changes are more likely. This supports further evaluation. It does not by itself confirm Alzheimer’s disease or predict how quickly symptoms will change.
Intermediate: the result is unclear and more testing is needed.

Confirming a diagnosis usually involves a full medical evaluation and, when needed, a brain scan (PET) or spinal fluid test — especially if a treatment that targets amyloid is being considered.

What these tests are not for

Screening people with no symptoms. A September 2026 NIH-funded study found that people in their 50s and 60s with higher blood levels of these proteins tended to have steeper declines on memory tests over five years. NIH notes that more study is needed before blood tests are used this way in the clinic.
Tracking treatment or predicting the future. These uses have not been established.

Memory problems have many causes

Thyroid problems, low vitamin B12, medication side effects, poor sleep, depression, hearing loss and other conditions can all affect memory, and many are treatable. That is why a blood test comes after a careful visit, not instead of one.

Questions to ask

Is a blood test appropriate for my symptoms?
Which test is it, and what is it cleared to do?
What happens if the result is positive, negative or intermediate?
Will insurance cover it?

Related guides

Sources

This guide is general education, not a diagnosis or a treatment plan. Your own clinician should guide decisions about your care.

Blood Tests for Alzheimer's Disease: What They Can Tell You in 2026