Antigen tests, such as the BinaxNOW Covid-19 antigen test, can be performed quickly with results available in 15 minutes. These tests are used to determine if a person is infectious. This kind of test will not be able to tell whether you have been previously infected with Covid, nor is it recommended for individuals experiencing severe symptoms or complications of Covid-19 infection. Such individuals should seek emergency medical attention. Individuals who have signs of illness but receive a negative rapid Covid antigen result should consult with their doctor or the health department for guidance on further testing and isolation precautions.