AUC Undermines AD Biomarker Discovery

Efforts are underway to accelerate precision medicine for late‐onset Alzheimer disease (AD). The realization of this endeavor can only be attained by identifying AD subtypes and developing methods to diagnose and treat each subtype. Liquid biopsies offer great potential for mounting this challenge. Identification of promising biomarkers requires evaluation of its ability to diagnose AD, and the area under the receiver operating characteristic curve (AUC) is commonly used for this purpose. This metric is equally weighted on the true positive rate (TPR) and false positive rate (FPR). When a given biomarker represents a single subtype, we expect the TPR to be relatively low as only a subset of AD cases are associated. Consequently, we hypothesized that screening based on AUC may discard valuable subtype biomarkers.