Simple Blood Test May Predict Alzheimer's Years Before Brain Scans Show Signs

Mass General Brigham researchers followed 317 cognitively healthy older adults for about eight years.

Higher plasma pTau217 levels predicted later amyloid buildup and cognitive decline, often before PET scans turned abnormal.

The findings suggest a blood test could flag Alzheimer’s risk earlier than brain imaging.

If validated, pTau217 could improve screening and speed up prevention trials and early intervention.