The SARS-CoV-2 Antigen Rapid Test Kit is a colloidal gold enhanced double antibody sandwich immunoassay for the qualitative determination of SARS-CoV-2 antigen. The test region (T) of the nitrocellulose membrane was immobilized with mouse anti-SARS-CoV-2 antibody 1 (Ab1), and the control region (C) was immobilized with Goat and anti-chicken IgY antibody (GAC). At the same time, the bonding pad of the test card was fixed with mouse anti-SARS-CoV-2 antibody 2 (Ab2) and chicken IgY (CIgY) which were both labeled by colloidal gold.
When the sample contains SARS-CoV-2 antigen is added to the sample well of the detection card, it will react with Ab2 to form complexes “antigen-Ab2-colloidal gold”. When the complexes migrate along the membrane, it can be captured by the Ab1 immobilized in the test region to form complexes “Ab1-antigen- Ab2-colloidal gold”, and a purple band appeared in the test region. The absence of this colored band in the test region suggests a negative result. A colored band always appears in the control region serving as procedural control regardless of the sample contains SARS-CoV-2 or not.