Scientists Get Closer to Blood Test for Alzheimer's Disease

Several studies have demonstrated an experimental blood test's accuracy in distinguishing between people with and without Alzheimer's disease, raising hopes of a simple pathway for diagnosing the disorder, reports the Associated Press . Some of the results were published in the Journal of the American Medical Association . The test identified people with Alzheimer's compared to no dementia or other types of dementia with accuracy ranging from 89 percent to 98 percent. The test concentrates on tau protein, determining that the p-tau217 variant is a more reliable indicator than amyloid. In a Lund University study, the p-tau217 test surpassed other measures for indicating who had Alzheimer's as verified by brain scans, with comparable accuracy to the scans and some spinal tests. Meanwhile, researchers at the University of California, San Francisco, found the test helped distinguish people with Alzheimer's from those with frontotemporal lobar degeneration with 96 percent accuracy. A Washington University in St. Louis study also found p-tau217 superior to other indicators for revealing which subjects had plaques in the brain. The U.S. National Institute on Aging's Eliezer Masliah said the new test "appears to be even more sensitive and more reliable" than previous methods, but larger and more diverse population studies are necessary.