Development of an ELISA for SARS-CoV-2 Detection Focusing on Antibodies against Nucleocapsid Protein

In late 2019, a novel viral disease, designated as SARS-CoV-2, emerged in China and rapidly propagated, ultimately resulting in a global pandemic. This virus has had a profound impact on human health and has caused significant financial losses for various societal sectors. Consequently, researchers are endeavoring to expedite the identification and control of this pathogen. The ELISA method has emerged as a valuable tool in the screening of large patient populations during infectious epidemics. In this study, the nucleocapsid protein (NP) of the SARS-CoV-2 virus was utilized to measure serum antibodies, which were obtained from the Avicenna Research Institute. The antigen was coated on each well of the plate, followed by the addition of serum samples from medical diagnostic laboratories (positive and negative sera measured by ELISA and PCR). To optimize the ELISA assay, a checkerboard titration was performed for all serum samples and antigens. The ELISA test was an indirect assay that could detect antibodies against NP.Finally, the cut-off, sensitivity, and specificity of the ELISA test were measured. The findings of the study indicated a 95% sensitivity and 92% specificity rate. Additionally, the intra-assay and inter-assay coefficient of variation (CV) values were recorded at 0.263% and 0.41%, respectively. These outcomes substantiate the remarkable precision and reliability of the ELISA test.In summary, the efficacy and precision of our kit in detecting antibodies targeting NP hold considerable promise. This innovative approach enhances diagnostic accuracy and holds significant potential for advancing antibody detection methodologies in the fields of virology and immunology.