Plasma and Cerebrospinal Fluid Levels of Amyloid β Proteins 1-40 and 1-42 in Alzheimer Disease

Although mean plasma Abeta40 levels are elevated in sporadic AD and influenced by Apo E genotype, measurement of plasma Abeta40 levels is not useful to support the clinical diagnosis of AD. Lower levels of CSF Abeta42 in the AD group are consistent with previous studies.