Blood Test Shows Highest p-tau217 Levels Tied to 38 Percent Five-Year Cognitive Impairment Risk

Individuals with the highest levels of the blood marker p-tau217 faced a 38 percent probability of developing cognitive impairment within five years and a 78 percent probability within ten years, according to a study of 2,684 healthy older adults. Researchers measured p-tau217 at enrollment and conducted annual cognitive assessments.

Over the follow-up period, 478 participants developed cognitive impairment.

The findings were published in JAMA and presented at the Alzheimer's Association International Conference in London. The test currently helps diagnose whether people already experiencing cognitive problems have Alzheimer's disease or another condition. Dr.

Reisa Sperling of the Mass General Brigham Neuroscience Institute, the study's senior author, advised healthy individuals to wait for testing until treatments become available. "Wait and get tested when you can potentially do something about it," she said. "At this point it wouldn't change what I would tell someone to do.

Drs. Suzanne Schindler of Washington University in St. Louis and David Wolk of the University of Pennsylvania wrote in an accompanying JAMA editorial that the test is not yet precise enough for individualized prognosis.

They described the results as a crucial piece of the puzzle. Jessica Langbaum of the Banner Alzheimer's Institute said people with a family history of Alzheimer's are already requesting the test, though she does not recommend it outside research settings. She noted that a predictive test would become important if trials show drugs can prevent or delay Alzheimer's before symptoms appear.