Implementing plasma p-tau217 and cognitive testing for Alzheimer's screening in low-education populations in central...

We evaluated a pragmatic screening strategy combining brief cognitive assessment with plasma phosphorylated tau217 (p-tau217) in an elderly health screening cohort.

Participants completed the Memory and Executive Screening (MES) test and plasma biomarker assessment. Cognitive impairment was defined using individualized residual norms derived from an internal reference sample. The p-tau217 thresholds were positive predictive value (PPV) -oriented and anchored to age- and cognitive status-specific prior probabilities of amyloid-β (Aβ) pathology.

MES-defined cognitive impairment (≤-2 standard deviation [SD] deviation after adjustment for demographics) was identified in 12.4% of participants. In cognitively unimpaired (CU) individuals, age-specific thresholds targeting a PPV of 0.7 yielded an overall p-tau217 positivity rate of 11.8%, increasing from 3.5% (< 60 years) to 6.3% (60-70 years) and 25.9% (≥70 years). Among cognitively impaired (CI) participants, 26.6% were p-tau217 positive.

This framework supports practical integration of plasma biomarkers into community-based screening, with longitudinal follow-up needed to further refine threshold selection.

Regression-based residual method reduced education bias, identifying 12.4% with cognitive impairment individuals. Fully automated chemiluminescent assay enabled practical, large-scale biomarker implementation. Brief screening strategy supports early detection, clinical trial recruitment, and resource allocation in under-resourced regions.