Rapid Antigen Test Kits work by detecting SARS-CoV-2 viral antigens through visual interpretation of colour development. Anti-SARS-CoV-2 antibodies are immobilised on the test region of the nitrocellulose membrane.
A sample is added to the extraction buffer which is optimised to release the SARS-CoV-2 antigens from specimen.
As the specimen migrates along the strip by capillary action and interacts with reagents on the membrane, the complex will be captured by the anti-SARS-CoV-2 antibodies at the test region.
Excess coloured particles are captured at the internal control zone. The presence of a coloured band in the test region indicates a positive result for the SARS-CoV-2 viral antigens, while its absence indicates a negative result.
A coloured band at the control region serves as a procedural control, indicating that the proper volume of specimen has been added and membrane wicking is working. Negative test results do not exclude infection with COVID-19 (so face masks, social distancing and good hygiene practice must be maintained).