Plasma p‐tau217 and p‐tau217/Aβ1‐42 are effective biomarkers for identifying CSF‐ and PET imaging‐diagnosed Alzheimer's disease: Insights for research and clinical practice

Plasma phosphorylated tau (p-tau)217 and p-tau217/amyloid beta (Aβ)1-42 demonstrated exceptional accuracy (area under the curve: 0.94-0.97) in detecting brain amyloid pathologies across both research (Southern China Aging Brain Initiative [SCABI]-1, SCABI-2) and real-world clinical practice (RCP) cohorts. Incorporating patient-specific factors (sex, age, apolipoprotein E ε4, cognitive status) improved diagnostic specificity in the clinical RCP cohort, aligning its performance with that of research cohorts. Plasma biomarkers, particularly p-tau217 and their ratios, showed robust correlations with cerebrospinal fluid biomarkers and positron emission tomography amyloid standardized uptake value ratios, underscoring their value as non-invasive diagnostic alternatives. Plasma p-tau217 and p-tau217/Aβ1-42 proved highly effective in diagnosing amyloid burden, offering a practical solution to bridge research advancements with real-world clinical practice.