Antigen testing is much faster and cheaper than the gold-standard tests that detect viral RNA using a technique called the polymerase chain reaction (PCR) which takes several hours in a specialist laboratory.
The antigen test looks for fragments of antigens within a person’s body to see if they are infected with the virus while the PCR tests can detect small amounts of viral genetic material (RNA), so a PCR test can be positive after a person stops being infectious.
PCR testing also requires complex facilities and elaborate training of operators, thus suffering from limit testing capacity, delayed results typically 24 hours to 48 hours and high costs. Both testing methods identify a current viral infection with the antigen result ready in under 15 minutes. No need for a laboratory, equipment or to wait for results with an antigen test.