What does a positive result in a rapid antigen test for COVID-19 indicate?

A positive result in a rapid antigen test for COVID-19 indicates the presence of SARS-CoV-2 antigens, which suggests a current infection. Antigens are specific proteins associated with the virus, and rapid antigen tests are designed to detect these proteins in a sample (typically from a nasal swab) during an active infection. This means that if the test returns a positive result, it is indicative of an ongoing infection with the virus at that moment.

In contrast, a positive result does not indicate a previous infection or the presence of antibodies; that would typically be assessed through antibody testing, which looks for the immune response rather than the virus itself. Additionally, a positive antigen test cannot rule out the presence of other respiratory viruses, nor does it provide any information regarding them. Therefore, the specificity of the rapid antigen test leads to the conclusion that a positive result points towards an active SARS-CoV-2 infection.