A simple blood test could reveal Alzheimer’s risk 10 years before symptoms

A major international study found that a simple blood test could help predict Alzheimer’s-related cognitive decline years before symptoms appear, with the highest-risk individuals facing a 38% chance of impairment within five years and an estimated 78% chance within 10 years. Scientists believe the discovery could pave the way for earlier intervention and future treatments designed to prevent Alzheimer’s before memory problems begin. A simple blood test could reveal Alzheimer’s risk 10 years before symptoms.

In a large international study, researchers found that older adults with very high levels of a particular blood biomarker faced a 38% chance of developing cognitive impairment within five years. Over 10 years, the estimated risk rose to 78%, although the longer-term findings were based on substantially less data. The findings offer new insight into the potential of blood tests to predict future cognitive problems in people who currently show no signs of impairment.

The research was led by scientists at the Mass General Brigham Neuroscience Institute and involved teams working across three continents. The results were presented at the Alzheimer’s Association International Conference and simultaneously published in JAMA. The study focused on phosphorylated tau 217 (p-tau217), a blood biomarker associated with Alzheimer’s disease.