To understand antigen testing, you have to know what an antigen is. “An antigen is a substance recognized by the body’s immune system, which can [then] respond by generating proteins called antibodies that specifically recognize that antigen.

It is a test on swabbed nasal samples that detects antigens (foreign substances that induce an immune response in the body) that are found on or within the SARS-CoV-2 virus. It is a point-of-care test, performed outside the conventional laboratory setting, and is used to quickly obtain a diagnostic result.