SD Biosensor Standard Q Covid-19 Antigen Rapid Self Test Kit is a rapid chromatographic immunoassay for the qualitative detection of specific antigens to SARS-CoV-2 present in human nasopharynx. This test is for administration by healthcare workers and labs only, as an aid to early diagnosis of SARS-CoV-2 infection in patient with clinical symptoms with SARS-CoV-2 infection. It provides only an initial screening test result. The result of this test should not be the sole basis for the diagnosis; confirmatory testing is required. Standard Q Covid-19 Ag Test has two pre-coated lines, "C" Control line, "T" Test line on the surface of the nitrocellulose membrane. Both the control line and test line in the result window are not visible before applying any specimens. The control line is used for procedural control and should always appear if the test procedure is performed properly and the test reagents of the control line are working. A colored test line would be visible in the result window if SARS-CoV-2 antigens are present in the specimen. The intensity of colored test line will vary depending upon the amount of SARS-CoV-2 antigen present in the specimen. If SARSCoV-2 antigens are not present in the specimen, then no color appears in the test line.