Standardization of preanalytical aspects of cerebrospinal fluid biomarker testing for Alzheimer's disease diagnosis: a consensus paper from the Alzheimer's Biomarkers Standardization Initiative.

Numerous studies show that the cerebrospinal fluid biomarkers total tau (T-tau), tau phosphorylated at threonine 181 (P-tau(181P)), and amyloid-β (1-42) (Aβ(1-42)) have high diagnostic accuracy for Alzheimer's disease. Variability in concentrations for Aβ(1-42), T-tau, and P-tau(181P) drives the need for standardization.Key issues were identified and discussed before the first meeting of the members of the Alzheimer's Biomarkers Standardization Initiative (ABSI). Subsequent ABSI consensus meetings focused on preanalytical issues.Consensus was reached on preanalytical issues such as the effects of fasting, different tube types, centrifugation, time and temperature before storage, storage temperature, repeated freeze/thaw cycles, and length of storage on concentrations of Aβ(1-42), T-tau, and P-tau(181P) in cerebrospinal fluid.The consensus reached on preanalytical issues and the recommendations put forward during the ABSI consensus meetings are presented in this paper.