SHOTS HEALTH NEWS – A new generation of blood tests is poised to change the way doctors determine whether patients with memory loss also have Alzheimer’s disease.
The tests detect substances in the blood that indicate the presence of sticky amyloid plaques in the brain — a hallmark of Alzheimer’s. So these tests have the potential to replace current diagnostic procedures, like costly PET scans and uncomfortable spinal taps.
Blood tests also promise to provide doctors with a quick way to identify patients who could benefit from new drugs that remove amyloid from the brain.
But the accuracy of the tests still varies widely.
“Some of them are really good, and some of them are really bad,” says Dr. Suzanne Schindler, a dementia specialist at Washington University School of Medicine in St. Louis.
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The search for plaques and tangles
Blood tests represent the latest advance in efforts to detect the buildup of amyloid plaques and fibrous tangles in the brain.
“It used to be that the only way you could definitively diagnose someone with Alzheimer disease is by doing an autopsy,” Schindler says.
Then, starting in the early 2000s, scientists found ways to detect plaques and tangles using PET scans and tests of spinal fluid. There are now versions of both approaches that are approved by the Food and Drug Administration.
But the scans are costly, and spinal taps are unpopular with many doctors and patients. Both also require expertise that is in short supply.
So Schindler and her colleagues got a lot of attention in 2019 when they published a paper showing that amyloid plaques could be revealed by a blood test.
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“Since then, I’ve probably had 100 people email me wanting a test,” Schindler says. “In many cases, they are people who had family members who had Alzheimer’s disease, and this is their biggest fear.”
Today, labs offer more than a dozen Alzheimer’s blood tests …