Fig. 4: Agreement of serological assays for SARS-CoV-2.
From: Evaluation of SARS-CoV-2 serology assays reveals a range of test performance
a, Percent agreement is plotted across all assay combinations, and values signify the binomial regression of the two assays across all tests. Samples were labeled ‘positive’ if any antibody isotype was detected for each assay. b, IgM or IgG LFA scores for each assay are compared to S/CO from three different ELISAs for all SARS-CoV-2 RT–PCR-positive samples. Biologically independent samples for each test are as follows: n = 126, Biomedomics; n = 126, Bioperfectus; n = 124, DecomBio; n = 128, DeepBlue; n = 114, Innovita; n = 127, Premier; n = 127, Sure; n = 128, UCP; n = 119, VivaChek; n = 124, Wondfo. Joint IgM/IgG signal is represented by a single band in Wondfo, so data were plotted as IgM or IgG depending on ELISA comparison. The F(ab′)2-specific secondary antibody used in our in-house ELISA preferentially binds the IgG light chain but per the manufacturer contains some reactivity for other isotypes (IgM and IgA); it is compared in b to IgG band intensity. For b, the box spans the 25th to 75th percentiles with median indicated by the black bar; whiskers show maximum and minimum value within 1.5× the interquartile range from the box.
