What will my COVID-19 antigen test results tell me?

Both the PCR and antigen tests check for SARS-CoV-2, the virus that causes an active COVID-19 infection. A PCR test detects the genetic material (RNA) of the virus. An antigen test detects a protein that is present on the virus. If you have a positive antigen test (regardless of PCR test results) and have had known exposure to and/or symptoms of COVID-19, you should follow the guidelines from the Centers for Disease Control and Prevention (CDC) for isolation. If your results are negative, this may suggest the virus was not present in the sample you provided. However, if your results were negative and you’re having symptoms of COVID-19, you may need to be tested with a COVID-19 PCR test.