evidence: Antigen tests are one type of rapid test that may help diagnose COVID-19. Some rapid tests can provide results in 15 minutes. But, they may not be as accurate as other types of tests, such as a PCR lab test. [...] In people who show symptoms of COVID-19, antigen testing is more reliable because there’s more virus to capture in the sample. [...] PCR covid tests remain the gold standard for diagnosing COVID-19.