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• Posted July 15, 2026

Blood Test May Predict Alzheimer's Risk Up To 10 Years Before Symptoms Begin

A simple blood test may accurately predict a person's risk of developing Alzheimer's symptoms up to a decade before they begin.

The test looks for an Alzheimer's biomarker called p-tau217.

"This is a critical step toward better understanding what p-tau217 can tell us about a person’s risk for cognitive impairment," said lead author Rachel Buckley, a cognitive neuroscientist at the Mass General Brigham Neuroscience Institute in Boston. "What really sets this work apart is that it estimates an individual's level of risk for cognitive impairment."

Researchers pooled data from more than 2,600 cognitively healthy older adults who underwent the blood test, brain scans and annual cognitive assessments.

The result: People with very high levels of p-tau217 had an estimated 38% risk of developing cognitive impairment within five years. That estimated risk increased to 78% over 10 years.

While the blood test recently received federal clearance, the authors said it's too soon to recommend it for people without symptoms.

"We do not yet have disease-modifying treatments for people who find out they are at high risk for developing cognitive impairment due to Alzheimer's disease," said senior and corresponding author Dr. Reisa Sperling, a neurologist at the Mass General Brigham Neuroscience Institute.

But, she said, that could change quickly if new therapies now in clinical trials prove successful. For now, the medical advice remains the same regardless of test results.

"Exercise regularly, maintain a healthy diet and prioritize sleep and overall wellness," Sperling said.

Future studies will follow more diverse populations over longer periods to confirm and refine the findings.

The findings were published today in the Journal of the American Medical Association.

More information

The BrightFocus Foundation has more on tau protein and Alzheimer's disease.

SOURCE: HealthDay TV, July 15, 2026