COVID-19 PCR Test Types
PCR (Polymerase Chain Reaction)
Taken to be the gold standard for the detection of SARS-CoV-2 (the virus that cause COVID-19), the PCR test is taken as a nasal or nasopharyngeal swab. The test is very sensitive. The downside is that the test can sometimes detect small amounts of viral particles after you have recovered form COVID-19.
The antigen test detects viral particles by using antibodies dissolved in a strip called a Lateral Flow Assay, similar to a pregnancy test in form. The test is not as sensitive as a PCR test but is useful for detecting when a person is in the most infectious stages of COVID-19. The main advantage is that is can be processed in 15-minutes, without expensive technology.
During and after COVID-19 infection, your body makes neutralising antibodies against the SARS-CoV-2 virus. These antibodies can be detected in a blood sample either in a lab on on a lateral flow assay. The test theoretically shows immunity against COVID-19. The disadvantage is that the levels of antibody may drop some weeks after COVID-19 infection but the immunity remains as undetectable mememory cells.