Blood test may predict timing of Alzheimer's symptoms

Researchers report a blood test that measures plasma p-tau217 and can estimate the age when a person may begin showing Alzheimer's symptoms, with an average margin of error of three to four years.

Researchers report a new blood test that estimates when someone may begin showing symptoms of Alzheimer's disease. The study, published in Nature Medicine, evaluates levels of a protein called p-tau217 in plasma. The model links p-tau217 to the brain accumulation of amyloid and tau and estimates symptom onset with a margin of error of about three to four years. The authors note the test is less costly and more accessible than brain imaging or spinal fluid tests. Key findings: - The model uses plasma p-tau217 levels, which reflect amyloid and tau accumulation in the brain. - Researchers reported the model can predict an individual's likely age of symptom onset within a three- to four-year margin of error. - Older participants tended to have a shorter interval between the first appearance of elevated p-tau217 and symptom onset than younger participants. - The study gives an example that elevated p-tau217 detected at age 60 was associated with symptom onset about 20 years later. - The research and comments in the article were attributed to investigators including Suzanne Schindler and Kellen Petersen. Summary: The reported blood test offers a way to estimate when Alzheimer's symptoms may begin and could help target participants for clinical trials. Researchers say further refinement and validation are needed before the approach could be applied in routine individual clinical care.