Plasma p-tau217 as a biomarker for Alzheimer's disease: diagnostic and prognostic value in clinical and population-based studies

Abstract Alzheimer's disease (AD) is the leading cause of dementia worldwide, and blood-based biomarkers are emerging as accessible diagnostic tools. Plasma phosphorylated tau at position 217 (p-tau217) has shown promise in early detection. To evaluate the diagnostic accuracy, prognostic value, and applicability of plasma p-tau217 in AD compared with other biomarkers. We conducted an integrative review on the PubMed, Scopus, Embase, and Cochrane Library databases (2018–2024). Eligible observational and diagnostic studies assessing p-tau217 in plasma were included. Study selection and quality assessment followed the Standards for Reporting of Diagnostic Accuracy (STARD) and Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. We analized 9 studies involving more than 6 thousand participants analyzed. Plasma p-tau217 demonstrated high accuracy (area under the curve [AUC]: 0.86–0.94) for detecting tau and amyloid pathology, outperforming p-tau181. It was effective in diverse populations, asymptomatic individuals, and primary care settings. Longitudinal data suggest predictive value for cognitive decline. Plasma p-tau217 is a reliable and non-invasive biomarker for AD, with applications in diagnosis, prognosis, and treatment monitoring. Standardization and multicenter validation are necessary before clinical implementation.