New blood test that screens for Alzheimer’s may be a step closer to reality, study suggests

Testing a person’s blood for a type of protein called phosphorylated tau, or p-tau, could be used to screen for Alzheimer’s disease with “high accuracy,” even before symptoms begin to show, a new study suggests.

Testing a person’s blood for a type of protein called phosphorylated tau, or p-tau, could be used to screen for Alzheimer’s disease with “high accuracy,” even before symptoms begin to show, a new study suggests. The study involved testing blood for a key biomarker of Alzheimer’s called p-tau217, which increases at the same time as other damaging proteins — beta amyloid and tau — build up in the brains of people with the disease. Currently, to identify the buildup of beta amyloid and tau in the brain, patients undergo a brain scan or spinal tap, which often can be inaccessible and costly. But this simple blood test was found to be up to 96% accurate in identifying elevated levels of beta amyloid and up to 97% accurate in identifying tau, according to the study published Monday in the journal JAMA Neurology. “What was impressive with these results is that the blood test was just as accurate as advanced testing like cerebrospinal fluid tests and brain scans at showing Alzheimer’s disease pathology in the brain,” Nicholas Ashton, a professor of neurochemistry at the University of Gothenburg in Sweden and one of the study’s lead authors, said in an email. The study findings came as no surprise to Ashton, who added that the scientific community has known for several years that using blood tests to measure tau or other biomarkers has the potential to assess Alzheimer’s disease risk. “Now we are close to these tests being prime-time and this study shows that,” he said. Alzheimer’s disease, a brain disorder that affects memory and thinking skills, is the most common type of dementia, according to the National Institutes of Health.