Rapid antigen tests are diagnostic tools used to quickly detect the presence of specific proteins from a virus, such as the SARS-CoV-2 virus responsible for COVID-19. These tests provide results in as little as 15 to 30 minutes, making them useful for screening in various settings, including homes, schools, and healthcare facilities. The tests work by collecting a sample, usually from the nose or throat, and applying it to a test strip. If the virus is present, a visible line appears on the strip, indicating a positive result. Rapid antigen tests are generally less sensitive than PCR tests, but they are valuable for quick assessments.