New Blood Test Predicts Alzheimer’s Risk Up to 10 Years in Advance
A new blood test measuring the biomarker p-tau217 may allow clinicians to predict the risk of cognitive impairment in healthy older adults up to a decade before symptoms appear, according to research presented at the Alzheimer’s Association International Conference in London and published in The Journal of the American Medical Association. The study, led by researchers at Harvard Medical School and the Mass General Brigham Neuroscience Institute, provides evidence that the test can detect signs of Alzheimer’s disease progression earlier than traditional diagnostic tools like PET scans.
Understanding the p-tau217 Biomarker
The test identifies levels of p-tau217, a modified form of the tau protein. In the brain, amyloid plaques can accumulate decades before memory loss begins, eventually triggering tau proteins to form tangles that cause neurons to collapse and die. According to lead author Rachel Buckley, an associate professor of neurology at Harvard Medical School, the p-tau217 biomarker helps identify the “tipping point” when amyloid buildup begins to cause the spread of disease. While PET scans were previously considered the earliest indicator of Alzheimer’s progression, researchers noted that p-tau217 can sometimes be detected years before abnormalities appear on amyloid PET scans.
Study Findings on Cognitive Risk
In one of the largest analyses of its kind, researchers tracked 2,684 cognitively healthy adults with an average age of 70 for up to a decade. The results indicated a clear correlation between biomarker levels and future cognitive decline: * Five-year risk: Symptom-free individuals with very high levels of p-tau217 had an estimated 38% chance of developing cognitive impairment. * Ten-year risk: The estimated risk for those with very high levels rose to 78%. * Moderate levels: Even participants with moderately elevated levels faced a 45% risk of cognitive decline over a 10-year period. Researchers noted that participants with very low levels of the biomarker maintained a low risk of cognitive impairment over the same timeframe.
Clinical Utility and Expert Caution
While the findings are promising, experts emphasize that the test should not currently be used in isolation for healthy individuals. Other experts, including Dr. Reisa Sperling of the Mass General Brigham Neuroscience Institute, advised healthy people to wait to seek testing until there are actionable medical interventions available. Wait and get tested when you can potentially do something about it,
Sperling said. At this point it wouldn’t change what I would tell someone to do.
I’d still tell them to eat well, sleep well, exercise a lot and stay engaged.
Future Implications for Alzheimer’s Treatment
The potential for early detection could transform how Alzheimer’s is managed. Researchers suggest that once verified, these blood tests could be used to recruit participants for clinical trials, allowing scientists to test drugs before the disease causes significant brain damage. If effective, these tests could eventually be used similarly to how cholesterol tests are used to estimate heart disease risk, guiding monitoring and patient counseling.