A novel method for detecting SARS-CoV-2 IgM and IgG based on the gold immune chromatography assay

A novel method was proposed based on gold immune chromatography assay (GICA) including the detection of antibodies targeting different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epitopes to improve the SARS-CoV-2 IgM and IgG detection performance. Sera from 282 confirmed Coronavirus Disease 2019 (COVID-19) patients were obtained at different times as the SARS-CoV-2 IgM or IgG experimental group. Sera from 148 uninfected and unvaccinated individuals were used as the control. The serum single-epitope IgM and IgG antibodies against SARS-CoV-2 were detected via GICA; the two epitope antibodies with high detection performance were used to construct a novel method, and then compared with the chemiluminescence immunoassay (CLIA). The diagnostic specificity and screening sensitivity of S2-IgM and N-IgM combined detection of serum SARS-CoV-2 IgM antibodies based on GICA were 99.32% and 98.81%, respectively, which were higher than those of the CLIA test (83.78% and 82.14%; P < 0.001). The diagnostic specificity of RBD-IgG and N-IgG combined detection in the serum was 100.00%, the same as that of CLIA. The novel method showed excellent screening sensitivity and diagnostic specificity for serum SARS-CoV-2 IgM and IgG, effectively avoiding omissions and misdiagnoses in the early clinical stages of screening and diagnosing COVID-19.