Potential of Blood- and CSF-Based Biomarkers for Alzheimer’s Disease Diagnostics

Currently, a diagnosis of Alzheimer’s disease (AD) depends on some combination of the expression of telltale symptoms, patterns of performance obtained from neuropsychological tests, and brain imaging. Recognition that AD-related pathology can be ongoing for as much as a decade prior to the appearance of symptoms is the impetus behind a tremendous research effort aimed at identifying and developing biomarkers for AD that are linked to pathology and can be used for early disease screening, early diagnosis, and disease monitoring. The long list of recent failures of AD clinical trials has increased the intensity of the search for biomarkers that would make possible early detection and earlier enrollment into clinical trials, hopefully increasing the chances of a successful outcome. This chapter reviews progress along these lines, with emphasis on highlighting the various biomarkers found in the blood and cerebrospinal fluid that are relevant to the early pathology of AD.