Detecting Alzheimer’s Biomarkers in the Blood Could Improve Early Diagnosis

Alzheimer’s disease is frequently diagnosed after the development of cognitive symptoms – including memory loss and impaired ability to complete routine tasks – when irreversible neurological damage has been done. In an effort to improve rates of early diagnosis and intervention, researchers at Washington University in St. Louis have developed a blood test that can detect some of the hallmarks of Alzheimer’s disease.

Patients with Alzheimer’s disease show the characteristic pathological accumulation of beta-amyloid plaques in their brains. While it’s unknown what effect this protein build-up has on the symptoms of Alzheimer’s, characterization of these plaques using PET-scans and spinal tap procedures are important measures of disease severity and progression.

Unfortunately, these diagnostic techniques are invasive and costly making them impractical for routine screening of older patients at risk of developing Alzheimer’s. According to the researchers – who presented their findings at the Alzheimer’s Association International Conferencein London – their blood test could detect beta-amyloid plaque accumulation during regular visits to a physician’s office.

“This kind of test could be used to screen many thousands of patients to identify those at risk for Alzheimer’s disease, and to start treatments before memory loss and brain damage,” Dr. Randall Bateman, Charles F. and Joanne Knight Distinguished Professor of Neurology at Washington University, told New Scientist.

Similar to a cholesterol test, the blood test detects circulating beta-amyloid and uses an established ratio to determine whether plaques might be building up in the brain. Since it’s believed that beta-amyloid plaques begin to form 15 to 20 years before a patient begins to show symptoms of Alzheimer’s, the blood test could offer an early indication that would allow physicians to prescribe dementia-slowing drugs as early as possible.

“I’m very positive about the test, but would like to see it validated,” said Dean Hartley of the Alzheimer’s Association. “It was a very small sample, and they’re trying to confirm it in an additional 180 people. But in time, if we can get a blood test, it will take us further, just as cholesterol tests did in the cardiovascular field.”