New sets of diagnosis criteria for AD have been proposed to address the low specificity (70%) of the previous ones, that could be one of the causes of failure of previous clinical trials. Among these new criteria, cerebrospinal fluid (CSF) biomarkers and positon emission tomography (PET) with new ligands of amyloid plaques and more recently tau deposition are indicators of the underlying histopathology of the disease, and can also be used to evaluate early intervention efficacy as they are pathologic in the preclinical phase of AD, its prodromal phase.