Measuring the level of Tau protein is to diagnose Alzheimer’s disease/neurodegenerative disease. Alzheimer’s disease is well known to feature neurofibrillary tangles that are composed of modified tau protein which is misfolded and abnormally shaped. I[u1] t`s containing hyperphosphorylated tau in full-length or truncated forms is another major pathological hallmark of Alzheimer’s disease. And promising p-Tau markers are emerging. The marker are p-Tau181, p-Tau217, and p-Tau231 etc. Plasma p-Tau181 has gained momentum as a biomarker since an initial report showed that plasma p-Tau181 concentrations in patients with Alzheimer’s disease correlated with tau-PET. Findings of subsequent independent studies strongly suggest that plasma pTau181 reflects Alzheimer’s disease-specific neuropathology. Promising p-Tau markers are emerging. the marker are pTau181, p-Tau217 and p-Tau231 etc. The plasma p-Tau217 can differentiate Alzheimer’s disease from non-Alzheimer’s disease dementias with high accuracy (96%), similar to the performance of established CSF or tau-PET biomarkers. Measuring the level of Tau protein is to diagnose Alzheimer’s disease/neurodegenerative disease.