Study Shows New Blood Test May Predict Alzheimer’s Risk
The study sought to determine the utility of a novel and commercially available immunoassay for plasma p-tau217 to detect AD pathology and evaluate reference ranges for abnormal amyloid β (Aβ) and longitudinal change across three selected cohorts
- By BSTQ Staff
A recent study has found that a commercially available plasma p-tau217 (phosphorylated tau 217) immunoassay accurately identified biological Alzheimer’s disease (AD), comparable with results using cerebrospinal fluid (CSF) biomarkers, with reproducible cut-offs across cohorts. What’s more, it detected longitudinal changes, including at the preclinical stage. P-tau is a specific blood biomarker for AD pathology, with p-tau217 considered to have the most utility. However, availability of p-tau217 tests for research and clinical use has been limited.
The study sought to determine the utility of a novel and commercially available immunoassay for plasma p-tau217 to detect AD pathology and evaluate reference ranges for abnormal amyloid β (Aβ) and longitudinal change across three selected cohorts: cross-sectional and longitudinal data from the Translational Biomarkers in Aging and Dementia (TRIAD) cohort (visits October 2017 through August 2021), Wisconsin Registry for Alzheimer’s Prevention (WRAP) cohort (visits February 2007 through November 2020) and cross-sectional data from the Sant Pau Initiative on Neurodegeneration (SPIN) cohort (baseline visits March 2009 through November 2021). Participants included individuals with and without cognitive impairment grouped by amyloid and tau (AT) status using PET or CSF biomarkers. Data were analyzed from February to June 2023.
Seven hundred and 86 participants (mean [SD] age, 66.3 [9.7] years; 504 females [64.1 percent] and 282 males [35.9 percent]) were included. High accuracy was observed in identifying elevated Aβ (area under the curve [AUC], 0.92-0.96; 95% CI, 0.89-0.99) and tau pathology (AUC, 0.93-0.97; 95% CI, 0.84-0.99) across all cohorts. These accuracies were comparable with CSF biomarkers in determining abnormal PET signal. The detection of abnormal Aβ pathology using a three-range reference yielded reproducible results and reduced confirmatory testing by approximately 80 percent. Longitudinally, plasma p-tau217 values showed an annual increase only in Aβ-positive individuals, with the highest increase observed in those with tau positivity.
References
Ashton, NJ, Brum, WS, Di Molfetta, G, et al. Diagnostic Accuracy of a Plasma Phosphorylated Tau 217 Immunoassay for Alzheimer Disease Pathology. Journal of the American Medical Association, Jan. 22, 2024. Accessed at jamanetwork.com/journals/jamaneurology/fullarticle/2813751?guestAccessKey=46653b11-2129-407d-ac0a-1fe7d79e32c6&utm.
