Many studies have already highlighted the relevance of plasma pTau181 in different CoUs, such as diagnosis, trial selection, and disease monitoring of patients with high-risk of AD.21, 22, 23 Furthermore, plasma pTau181 has also been reported to be increased in Aβ-PET positive but still tau-PET-negative subjects, which suggests a specific sensitivity of plasma pTau181 for early AD pathology.19 This evidence concerns the gene MAPT and Alzheimer disease.