Figure 1
From: Agreement between commercially available ELISA and in-house Luminex SARS-CoV-2 antibody immunoassays
Classification of samples by ELISA and Luminex immunoassays for specific IgG, IgM and IgA. The categories in the X-axis refer to the classification of the ELISA assay (negative or positive). The Y-axis indicates the Luminex assay result in log10-transformed median fluorescence intensity (MFI). The seropositivity cutoff is shown in dashed lines (mean plus 3 SD of prepandemic samples). The color classification in concordant (black) versus discordant (grey) sample results between Luminex and ELISA tests is based on the combination of all antigens within each isotype for Luminex. That is, seropositivity and seronegativity were calculated per each immunoglobulin with the combination of all antigens from the Luminex assay, and those were compared with the ELISA result to subsequently define concordant and discordant samples between tests. The figure illustrates the lower specificity of the ELISA assay for IgM/A (elevated number of false positives) compared to the Luminex IgA and IgM assays, and the higher sensitivity of the IgG Luminex for the detection of positive samples that had been classified as negative by ELISA.
