MAPT and Alzheimer disease: With respect to p-tau biomarkers, the robustness ranges from low to high effect size from preclinical AD to prodromal AD, respectively, with the highest levels in AD dementia with p-tau 181 and also p-tau 231 both not performing as well as p-tau 217 [79, 80], positing that blood-based biomarkers may do better in later rather than early disease.