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

INTRODUCTION: We evaluated a pragmatic screening strategy combining brief cognitive assessment with plasma phosphorylated tau217 (p-tau217) in an elderly health screening cohort. METHODS: 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. RESULTS: 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. DISCUSSION: This framework supports practical integration of plasma biomarkers into community-based screening, with longitudinal follow-up needed to further refine threshold selection. HIGHLIGHTS: 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.