Covid Antigen tests are immunoassays that detect the presence of a specific viral antigen, which indicates current viral infection. Antigen tests are currently authorized to be performed on nasopharyngeal, nasal swab, or saliva specimens placed directly into the assay’s extraction buffer or reagent.

Antigen tests produce results quickly (within approximately 15–30 minutes). Antigen tests for SARS-CoV-2 are generally less sensitive than real-time reverse transcription polymerase chain reaction (RT-PCR), which detect and amplify the presence of viral nucleic acid.