Laboratory biomarkers in Alzheimer's disease.

Diagnosis and monitoring of Alzheimer's disease and the related dementias have long depended principally on clinical examination, especially cognitive testing. Establishment of biomarkers, which might assist in diagnosis or tracking of disease progression, would be a highly valuable addition to the care of patients. Such biomarkers are potentially available from body fluids and tissues as well as from brain imaging data. As specific disease-modifying therapies for Alzheimer's disease are developed, biomarkers may improve diagnostic accuracy and facilitate clinical trials, allowing a better gauge of treatment response. In this review, we focus on biomarkers in cerebrospinal fluid and plasma, including measurements of the proteins tau and beta-amyloid.