title: Confounding factors influencing amyloid Beta concentration in cerebrospinal fluid.
abstract: Background. Patients afflicted with Alzheimer's disease (AD) exhibit a decrease in the cerebrospinal fluid (CSF) concentration of the 42 amino acid form of beta-amyloid (Abeta(42)). However, a high discrepancy between different centers in measured Abeta(42) levels reduces the utility of this biomarker as a diagnostic tool and in monitoring the effect of disease modifying drugs. Preanalytical and analytical confounding factors were examined with respect to their effect on the measured Abeta(42) level. Methods. Aliquots of CSF samples were either treated differently prior to Abeta(42) measurement or analyzed using different commercially available xMAP or ELISA assays. Results. Confounding factors affecting CSF Abeta(42) levels were storage in different types of test tubes, dilution with detergent-containing buffer, plasma contamination, heat treatment, and the origin of the immunoassays used for quantification. Conclusion. In order to conduct multicenter studies, a standardized protocol to minimize preanalytical and analytical confounding factors is warranted.
authors.affiliation: Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at University of Gothenburg, 431 80 Mölndal, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Bjerke
authors.forename: Erik
authors.initials: E
authors.lastname: Portelius
authors.forename: Lennart
authors.initials: L
authors.lastname: Minthon
authors.forename: Anders
authors.initials: A
authors.lastname: Wallin
authors.forename: Henrik
authors.initials: H
authors.lastname: Anckarsäter
authors.forename: Rolf
authors.initials: R
authors.lastname: Anckarsäter
authors.forename: Niels
authors.initials: N
authors.lastname: Andreasen
authors.forename: Henrik
authors.initials: H
authors.lastname: Zetterberg
authors.forename: Ulf
authors.initials: U
authors.lastname: Andreasson
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
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