Fig. 6
From: Towards a unified protocol for handling of CSF before β-amyloid measurements
CSF collection gradient. Aβ42EI (a), Aβ40EI (b), Aβ42/Aβ40EI (c), Aβ42MSD (d), Aβ40MSD (e), and Aβ42/Aβ40MSD (f) in the second (P2), third (P3), and fourth (P4) 5-ml portions of 20 ml CSF collected after discarding the first 2 ml (10 patients). Data are shown as the percentage of biomarker levels in the first portion. The gray areas represent 95–105% and 90–110% ranges the EI and MSD assays, respectively, that were set based on the inter-assay CVs as described in the “Materials and methods” section. The mean biomarker levels in the second to fourth fractions were all within 95–105% range of the first fractions and, therefore, were not tested in statistical analysis. Horizontal lines and error bars represent mean ± SEM. Abbreviations: Aβ, β-amyloid; EUROIMMUN; MSD, Mesoscale discovery; P, portion; SEM, standard error of mean