Plasma Phospho-tau217: Homing in on a Plasma Biomarker for Alzheimer Disease?

Plasma tau and neurofilament light chain (NfL) levels may be useful biomarkers for Alzheimer disease (AD). Now, researchers have analyzed plasma tau phosphorylated at threonine 217 (P-tau217) as a diagnostic biomarker for AD in 1402 participants from three cohorts in Arizona, Sweden, and Colombia. The primary outcome was the discriminative accuracy of plasma P-tau217 for AD. A secondary outcome was the association of plasma P-tau217 levels with tau pathology.

In the Arizona cohort (mean age, 83.5 years; 38% women), plasma P-tau217 levels had better discriminatory accuracy for neuropathologically defined AD than plasma P-tau181 and NfL levels and also were associated with the postmortem density of neurofibrillary tangles. In the Swedish cohor…