Overview
- A pooled analysis published in JAMA and presented at AAIC found that very high blood levels of phosphorylated tau 217 (p‑tau217) strongly predict future cognitive impairment, with an estimated 38% risk at five years and 78% risk at 10 years for the highest levels.
- The study combined data from about 2,700 cognitively unimpaired adults from six research cohorts with an average follow‑up of nearly five years, giving the five‑year risk estimates greater confidence than the decade estimates.
- On Wednesday, July 15, 2026 researchers emphasized that p‑tau217 added prognostic information beyond PET brain scans and APOE genotype, meaning the blood measure can refine risk estimates beyond existing tests.
- A UK pilot called BriDGe is rolling out p‑tau181 and p‑tau217 testing through more than 50 GP surgeries in central and northern Scotland to refer up to 500 patients and evaluate real‑world primary care use of the assays.
- Experts warn the tests are not ready for routine screening of asymptomatic people because levels can be affected by age, kidney function, obesity and underrepresentation of diverse groups, so near‑term use should focus on trial recruitment and carefully monitored clinical implementation.