FDA Approves Blood Test to Help Diagnose Alzheimer’s

The U.S. Food and Drug Administration (FDA) has green-lit a blood test that can help doctors diagnose Alzheimer’s disease, the most common form of dementia. It is the first blood test to be cleared by the FDA for the disease, which affects more than 7 million older Americans and is marked by a decline in memory and thinking skills.

The test, called Lumipulse, can detect abnormal clumps of protein in the brain, known as amyloid plaques. These plaques disrupt brain cell function and are a hallmark of Alzheimer’s.

PET scans and spinal fluid tests can also detect amyloid plaques and have been used for years to help doctors diagnose Alzheimer’s. But the tests are expensive and, in the case of the lumbar puncture, invasive. They can also be inaccessible for people in rural areas. Lumipulse, on the other hand, requires only a blood draw in patients 55 and older who are showing signs and symptoms of the disease.

“Having a blood test just makes it so much easier in being able to make a diagnosis of Alzheimer’s disease,” said Charles Bernick, M.D., a neurologist with the Cleveland Clinic Lou Ruvo Center for Brain Health, based in Las Vegas.

In its news release, the test’s manufacturer, Fujirebio Diagnostics, didn’t specify the cost of the test.

People without symptoms shouldn’t test 

The newly approved blood test measures two proteins in the liquid part of the blood, known as plasma, and then calculates the ratio of these proteins, which is “correlated to the presence or absence of amyloid plaques in the patient’s brain, reducing the need for a PET scan,” the FDA said.

The test is only meant for older adults who are experiencing symptoms of Alzheimer’s disease; it is not a screening test. What’s more, the FDA said, the results should be used along with “other clinical evaluations or additional tests” to determine treatment options. In addition to brain imaging and lumbar punctures, doctors often use neurological exams and cognitive tests, for example, to diagnose a patient with Alzheimer’s disease. “It still becomes a diagnosis where you have to really look at the whole picture,” Bernick said.

In recent years, the FDA has approved two medications for the treatment of Alzheimer’s — Kisunla (donanemab) and Leqembi (lecanemab). These drugs, which are given by infusion, don’t cure the disease but can help to slow the rate of decline in people in its early stages. Because they work by clearing amyloid plaques from the brain, the presence of amyloid must be confirmed before they can be prescribed.

“They carry some risk. So if you’re going to use them or utilize them, you’ve got to be pretty sure the person has that protein in the brain,” Bernick said. Risks can include swelling and bleeding in the brain.