Upwards Drift Of Cerebrospinal Fluid Amyloid-Beta 42 Over Twelve Years In A Consecutive Clinical Cohort

Amyloid-beta 1-42 (A beta(1-42)) measured in the cerebrospinal fluid (CSF) can be used as a diagnostic biomarker for Alzheimer's disease (AD) but an upward drift when using the INNOTEST ELISA has been suggested. We investigated the upwards drift of A beta(1-42) levels over a period of twelve years in a consecutive memory clinic cohort. We found a significant increase in A beta(1-42) from 2008 to 2019 independent of changes in tau. New methods for the quantification of CSF A beta(1-42) levels are being implemented but awareness of this upwards drift is crucial during the diagnostic work-up and when selecting historical samples for research.