Plasma phosphorylated tau species have been recently proposed as peripheral markers of Alzheimer's disease (AD) pathology. In this cross-sectional study including 91 subjects, plasma and cerebrospinal fluid (CSF) p-tau181 and p-tau231 levels were elevated in the early symptomatic stages of AD. Plasma p-tau231 and p-tau181 were strongly related to CSF phosphorylated tau, total tau and amyloid and exhibited a high accuracy - close to CSF p-tau231 and p-tau181 - to identify AD already in the early stage of the disease. The findings might support the use as diagnostic and prognostic peripheral AD biomarkers in both research and clinical settings.
