title: Comparison of immunosorbent assays for the quantification of biomarkers for Alzheimer's disease in human cerebrospinal fluid.
abstract: BACKGROUND
  The clinical diagnosis of Alzheimer's disease in early stages may be substantiated by the quantification of the biomarkers Abeta42, Abeta40 and total-Tau (t-Tau) in cerebrospinal fluid (CSF). Different commercially available immunosorbent assays yield reliable results, yet the absolute values obtained may differ in between tests.
  
  
  METHODS
  We used CSF samples from patients that reported to our memory clinic. Enzyme-linked immunosorbent assays obtained from Innogenetics were used for the quantification of Abeta42 and t-Tau, test kits from IBL International were used to determine Abeta42 and Abeta40 concentrations. The multiplex assay system obtained from Mesoscale Discovery (MSD) Systems was used for the quantification of all three biomarkers.
  
  
  RESULTS
  For all biomarkers, the absolute values obtained with different test systems differ. However, the data sets highly correlate for all comparisons, with the MSD test system proving to be slightly more sensitive. Correlation coefficients (c) for the Abeta42 and Abeta40 quantifications lie between c = 0.80 and c = 0.87, and for the t-Tau quantifications we determined c = 0.99.
  
  
  CONCLUSIONS
  We conclude that all assays evaluated give reliable results, yet absolute values obtained have to be assessed differently within the framework of diagnostic procedures, depending on the system used.
authors.affiliation: Department of Psychiatry and Psychotherapy, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Berlin, Germany. carola.schipke@charite.de
authors.forename: C G
authors.initials: CG
authors.lastname: Schipke
authors.forename: S
authors.initials: S
authors.lastname: Prokop
authors.forename: F L
authors.initials: FL
authors.lastname: Heppner
authors.forename: I
authors.initials: I
authors.lastname: Heuser
authors.forename: O
authors.initials: O
authors.lastname: Peters
mesh_terms: D000544:Alzheimer Disease / Q000134:cerebrospinal fluid*; D016229:Amyloid beta-Peptides / Q000134:cerebrospinal fluid; D015415:Biomarkers / Q000134:cerebrospinal fluid*; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007118:Immunoassay; D007163:Immunosorbent Techniques; D016014:Linear Models; D010446:Peptide Fragments / Q000134:cerebrospinal fluid; D016875:tau Proteins / Q000134:cerebrospinal fluid
chemical_list: D016229:Amyloid beta-Peptides; D015415:Biomarkers; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); D016875:tau Proteins