Accurate and rapid diagnosis of coronavirus disease 2019 (COVID-19) is critical for proper care and identification of affected individuals. This led to early availability of many serological assays in the market, but with limited validation. In this study, we aimed to validate the serological assays based on different techniques. We evaluated 15 different assays based on four immunoassay techniques in 235 patients. The most sensitive kits employed were as follows: immunochromatography (Zybio severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] IgM/IgG Antibody Assay Kit - 83%), ELISA (Aeskulisa SARS-CoV-2 NP IgG -88.1%), chemiluminescence (Alinity SARS-CoV-2 IgG - 82.2%), and immunofluorescence (Lifotronic FA160 (Shenzhen SARS-CoV-2 Assay Kit [IgG]) - 88.9%). The kits by Uniper (Singuway Biotec COVID-19 IgM/IgG Presumptive Kit), Genrui 2019-nCoV IgM/IgG Test Kit, Wondfu SARS-CoV-2 Antibody Test, and Aeskulisa SARS-CoV-2 NP IgG exhibited 100% specificity, whereas IgG assay using Lifotronic FA160 (Shenzhen SARS-CoV-2 Assay Kit) exhibited the lowest specificity at 58%. Maximum agreement was observed between Aeskulisa SARS-CoV-2 NP IgG and Alinity SARS-CoV-2 IgG at 94%. Serological tests are practical alternatives, but their reliability depends on critical validation. The COVID-19 pandemic warranted investment in healthcare research at both the national and international levels.
Keywords: IgG; IgM; antibodies; coronavirus; serological assays.