Fig. 2.
CSF storage at − 20 °C and − 80 °C. Aβ42EI (a), Aβ40EI (b), Aβ42/Aβ40EI (c), Aβ42MSD (d), Aβ40MSD (e), and Aβ42/Aβ40MSD (f) in CSF samples that were stored at either − 20 °C or − 80 °C for 2 weeks after collection (10 patients, 4 CSF tubes per patient). Data are shown as the percentage of biomarker levels in fresh, non-processed, CSF samples (from the same donor) that were analyzed within hours after LP. The gray areas represent 95–105% and 90–110% ranges for the EI and MSD assays, respectively, that were set based on the inter-assay CVs as described in the “Materials and methods” section. Changes in the mean biomarker levels were all within 95–105% range of baseline at both temperatures and, therefore, were not tested in the statistical analysis. Horizontal lines and error bars represent mean ± SEM. Abbreviations: Aβ, β-amyloid; EI, EUROIMMUN; MSD, Mesoscale discovery; SEM, standard error of mean