GROUNDBREAKING findings indicate that a commercially available plasma p-tau217 immunoassay demonstrates diagnostic accuracy comparable to cerebrospinal fluid (CSF) biomarkers for identifying Alzheimer’s disease (AD) pathology. This assay was effective in detecting abnormal amyloid β (Aβ) and tau pathologies, with results consistent across multiple cohorts and showing longitudinal changes. The study provides valuable insights into the potential clinical utility of plasma p-tau217 as a reliable diagnostic tool for AD.
The study utilised data from three observational cohorts: the Translational Biomarkers in Aging and Dementia (TRIAD) cohort, the Wisconsin Registry for Alzheimer’s Prevention (WRAP) cohort, and the Sant Pau Initiative on Neurodegeneration (SPIN) cohort. It included 786 participants, with an average age of 66.3 years. The participants were grouped by amyloid and tau status, assessed via positron emission tomography (PET) and cerebrospinal fluid (CSF) biomarkers. The p-tau217 immunoassay demonstrated high diagnostic accuracy, with an area under the curve (AUC) ranging from 0.92 to 0.96 for Aβ detection, and from 0.93 to 0.97 for tau pathology. These results were consistent across all cohorts, with the assay achieving reproducible detection of abnormal Aβ pathology. Additionally, the plasma p-tau217 assay identified longitudinal changes in tau and Aβ positivity, with the greatest increase observed in individuals showing both Aβ and tau pathology.
The results of this study highlight the potential of plasma p-tau217 as a diagnostic biomarker for Alzheimer’s disease. With its high accuracy in detecting both Aβ and tau pathologies and its ability to track disease progression, this assay could play an essential role in clinical settings, facilitating early and reliable diagnosis of AD. Its widespread availability could significantly reduce the need for more invasive and expensive diagnostic procedures, such as CSF sampling or PET imaging. As research into AD biomarkers continues to evolve, further investigation into the implementation of this plasma test across diverse populations and clinical environments will be important for understanding its broader impact on patient care and disease management.
Katrina Thornber, EMJ
Reference
Ashton NJ et al. Diagnostic accuracy of a plasma phosphorylated tau 217 immunoassay for alzheimer disease pathology. JAMA Neurol. 2024;81(3):255-63.
