The ability to diagnose Alzheimer’s disease simply and cost-effectively took a major step forward in May 2025, when the FDA approved the first blood test for early detection of the condition. It’s intended for people ages 55 or older with signs or symptoms of the disease.
The test, called Lumipulse, isn’t the only one of its kind to look for Alzheimer’s blood markers. But it’s the only one that has made it through the challenging regulatory approval process, a milestone that’s considered a game changer.
To find out about the significance of this development and what this could mean for Alzheimer’s diagnosis, we turned to Dr. Andrew Budson, lecturer in neurology at Harvard Medical School and chief of Cognitive and Behavioral Neurology at VA Boston Healthcare System.
Q. Why is Lumipulse being watched so closely when doctors already can order similar blood tests for patients?
Dr. Budson: A number of accurate Alzheimer’s blood tests are available for clinical use, and some blood tests have been marketed directly to consumers. But without FDA approval, FDA safety regulation, and public and private insurance coverage, the tests have not been part of the standard of care for diagnosis — they’ve just been novel tests that people could pay for out of their own pocket. For example, testing might cost between $300 and $1,750 at some companies. Financial assistance is sometimes available.
Instead, we’ve relied on two other, more complicated, invasive, and costly types of FDA-approved tests that are covered by insurance to confirm the presence of Alzheimer’s: a positron emission tomography (PET) scan of the brain and a lumbar puncture, or “spinal tap,” which can detect disease biomarkers in a sample of fluid surrounding the brain and spinal cord.
Q. How does the FDA approval of Lumipulse change things?
Dr. Budson: The approval means that the blood test has been evaluated by scientists, is doing what it claims, and has the potential to be beneficial in people’s care.
The next step is for insurance to consider covering it, particularly Medicare and Medicaid. If that happens, which is expected soon, the test will likely become the standard of care. We’ll have a pathway for the rapid detection of Alzheimer’s, which will allow us to start treatment immediately.
Q. How does Lumipulse work?
Dr. Budson: The test analyzes a blood sample to look for several proteins that are characteristic of Alzheimer’s disease. It calculates the ratio of amyloid-beta 40 (which is naturally present in the brain and considered normal) to amyloid-beta 42 (which is involved in forming Alzheimer’s brain plaques). The test also looks for a type of tau protein (phosphorylated tau 217) that causes tangles in brain cells.
About 80% of the time, the blood test is either highly positive or highly negative, a result that’s accurate more than 90% of the time. About 20% of the time, the test is inconclusive.
Q. How might you and other physicians use Lumipulse, if it’s covered by insurance?
Dr. Budson: Here is the scenario I envision: The primary care provider identifies a patient with memory complaints and cognitive impairment as determined by a sensitive but brief cognitive screening test. The patient has blood tests to look for vitamin deficiencies and thyroid disorders and an MRI scan to look for brain tumors, fluid collections, and other structural problems. If the blood tests and the MRI do not provide answers, the doctor then orders the approved blood test to look for Alzheimer’s markers.
Q. In that scenario, how are the blood test results used?
Dr. Budson: If the blood test is clearly negative, the patient is told the reassuring news, but also told that their memory problems will be readdressed in six months. If something is still clearly wrong, the patient is referred to a memory specialist to look for other causes of dementia. If the test is inconclusive, the patient is referred to a memory specialist for either an amyloid PET scan or a lumbar puncture to determine the correct diagnosis.
If the blood test comes back positive, the patient is referred to a neurologist or another specialist for treatment with an amyloid-targeting therapy — donanemab (Kisunla) or lecanemab (Leqembi). These medicines remove amyloid plaques from the brain, hopefully before too much damage is done. It’s not a cure, but it slows the disease process. And studies show that the earlier you intervene with treatment for someone with symptomatic Alzheimer’s in early stages, the more effective the medications will be.
Q. Do you anticipate that other blood tests for Alzheimer’s will be approved?
Dr. Budson: Yes, I expect several other tests will quickly gain FDA approval. Because we have disease-modifying treatments for Alzheimer’s disease, there is now an imperative to detect and treat our patients quickly.
Just like in a patient in whom cancer is detected, the treatment doesn’t need to be initiated in a week, but six months is too long, and treatment would ideally begin within two months. Blood-based biomarkers will be crucial to help make this scenario into a reality.
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