Prompt COVID-19 diagnosis is urgently required to support infection control measures. Currently available serological tests for measuring SARS-CoV-2 antibodies use different target antigens, although their sensitivity and specificity presents a challenge. We aimed to develop an “in-house” serological ELISA to measure antibodies against SARS-CoV-2 by combining different protein antigens. Sera ( n = 44) from COVID-19-confirmed patients were evaluated against different SARS-CoV-2 protein antigens and all potential combinations using ELISA. Patients’ sera were also evaluated against commercially available ELISA diagnostic kits. The mixture containing RBD 2.5 μg/mL, S2 1 μg/mL and N 1.5 μg/mL was found to be the most potent. Plates were incubated with patients’ sera (1:100), and goat anti-human alkaline phosphatase-conjugated IgG, ΙgM and IgA antibody was added. The cut-off value for each assay was determined using the mean optical density plus two standard deviations of pre-pandemic controls. The “in-house” ELISA displayed 91% sensitivity and 97% specificity for IgG antibodies, whereas its sensitivity and specificity for IgM and IgA were 75% and 95% and 73% and 91%, respectively. The “in-house” ELISA developed here combined three SARS-CoV-2 antigens (RBD, S2 and N) as capture antigens and displayed comparable and even higher sensitivity and specificity than otherwise quite reliable commercially available ELISA diagnostic kits.
【저자키워드】 antibodies, SARS-CoV-2, Serological tests, 【초록키워드】 serological test, IgG, IgM, infection control, antibody, diagnostic, ELISA, Antigen, sensitivity, specificity, SARS-CoV-2 antibody, Measures, Sensitivity and specificity, IgG antibodies, RBD, IgA, sera, Patient, COVID-19 diagnosis, antigens, optical, SARS-CoV-2 antigen, serological, Combination, Support, Standard deviation, cut-off value, SARS-CoV-2 protein, protein antigens, controls, develop, evaluated, required, was determined, added, comparable, the mean, incubated, alkaline, capture antigen, Plate, 【제목키워드】 COVID-19, ELISA, Selection, development,