MAPT and Alzheimer disease: In contrast to tau, amyloid‐based plasma biomarkers, such as Aβ42/Aβ40, have a lower AUC (approximately 0.75) for distinguishing normal controls from AD,210 with similarly lower AUCs for identifying individuals with Aβ cerebrospinal fluid (AUC = 0.86)211 or brain PET Aβ (AUC = 0.75).210