MAPT and Alzheimer disease: Blood biomarker discovery has been a topic of active research in AD during the last few years, and the following factors are related to AD pathology, the phosphorylated tau protein (p-tau), amyloid-ß (Aß42), and Aß42/Aß40, which have been in the limelight because these biomarkers are well related to the pathology of AD as seen in the CSF and imaging analysis.