A blood test may predict the start of Alzheimer's symptoms years in advance

Key Points:

• Researchers have identified a blood test measuring p-tau217 that may predict the likelihood of healthy older adults developing Alzheimer's symptoms within five to 10 years, potentially aiding early identification for clinical trials.
• The study found that individuals with very high p-tau217 levels had a 38% risk of cognitive impairment at five years, rising to 78% at 10 years, while those with low levels had a correspondingly low risk.
• Experts caution that the test is not yet ready for routine use in healthy individuals, emphasizing lifestyle measures and awaiting effective treatments before widespread screening.
• The findings, published in JAMA and presented at the Alzheimer’s Association International Conference, provide insight into the gradual buildup of amyloid plaques and tau tangles linked to Alzheimer's progression.
• Limitations include a smaller number of participants tracked for a full decade and potential confounding factors like other health conditions, meaning the test is not yet precise enough for individualized prognosis.