Plasma biomarker progression across the Alzheimer's disease amyloid beta and tau positron emission tomography trajectories

INTRODUCTION: With increased uptake in disease-modifying treatments for amyloid beta (Aβ) removal, it is important to measure performance of highly sensitive plasma biomarkers to detect the presence of Aβ and tau in cognitively impaired populations. METHODS: In this study, we investigated a large set of plasma biomarkers for their capability to predict Aβ and tau positron emission tomography (PET) and their association with increasing Aβ and tau burden. RESULTS: From the biomarkers assessed, tau phosphorylated at threonine 217 (pTau217) showed the largest increases across the full range of Aβ and tau levels. Furthermore, pTau217/Aβ42 had the smallest proportion of participants in the intermediate zone (∼4%) to predict Aβ status using a 90/90% dual cut-off for sensitivity and specificity, with < 20% of participants in the intermediate zone using the 95/95% dual cut-off. DISCUSSION: While the studied biomarkers proved their utility to predict Aβ and tau PET at their respective thresholds, each has separate quantified responses to Aβ and tau aggregation.