This ELISA kit uses Indirect-ELISA as the method to qualitatively detect the SARS-CoV-2 Spike protein IgM in the sample. The micro ELISA plate provided in this kit is pre-coated with purified SARS-CoV-2 Spike protein (PKSR030489) antigen, after adding samples to wells, the SARS-CoV-2 Spike protein IgM in the samples will combine with the pre-coated SARS-CoV-2 Spike protein antigen. After washing completely, add Horseradish Peroxidase (HRP) conjugated mouse anti human IgM to develop the antigen-antibody-HRP conjugated secondary antibody complex. Free components are washed away, then the substrate solution is added to each well. Only those wells that contain SARS-CoV-2 Spike protein IgM and HRP conjugated anti-human IgM will appear blue in color. The enzyme-substrate reaction is terminated by the addition of stop solution and the color turns yellow. The optical density (OD) is measured spectrophotometrically at a wavelength of 450 ± 2 nm. Compared with the CUT OFF value to judge whether SARS-CoV-2 Spike protein IgM exists in the tested samples or not.

SARS-CoV-2, the causative viral agent of the disease COVID-19, is a coronavirus which bears the transmembrane glycoprotein spikes (S protein) typical of viruses in its clade. These spikes are a prominent target of human immune responses and have been found to be highly immunogenic. The receptor-binding domain (RBD) of the S protein is particularly targeted by neutralising antibodies.