A positive viral test result means that it is likely you are currently infected with COVID-19. A negative viral test result means that it is unlikely you were infected at the time of sample collection. However, sometimes there is not enough virus present early in an infection to detect and you may still be infectious or become sick later on. It is also possible for you to be exposed and become infected with the virus after your test. As with any medical test, inaccurate results (i.e., false positives or negatives) are possible. For this reason, it is important that you continue taking preventative measures such as wearing a mask and social distancing.
A positive antibody test result means you may have antibodies from an infection with the virus that causes COVID-19. However, there is a chance that a positive result means you have antibodies from an infection with a different virus from the same family of viruses (called coronaviruses). Having antibodies to the virus that causes COVID-19 may provide protection from getting infected with the virus again. But even if it does, it is unknown how much protection the antibodies provide or how long this protection lasts. A negative antibody test means you may not have ever had COVID-19 or you may have a current infection. It typically takes 1–3 weeks after infection for your body to make antibodies, so if you are early on in your infection the antibody test may be negative.