Myth: You may have heard the myth that if you test negative for Covid-19 that it means you definitely don’t have Covid-19

This is not true. With tests for Covid-19 there is always the possibility of a false negative test, meaning a person tests negative even though the virus is inside their body. This can happen for a number of reasons. First, if a person is having a PCR test, also known as a molecular test, this usually involves a long thin swab being pushed into their nose and to the back of their throat. But if this swab is not pushed far back enough this can cause a false negative. Second, the person might be infected with the virus but there might only be very small amounts of the virus in their body – this can happen early on in the infection – and if this is the case, a test might not detect those small amounts of virus. Third, there can be problems with the test kits themselves that cause some people who are positive to test negative. For these reasons, we have to interpret the results of Covid-19 tests with additional information about the patient, how the patient is feeling, who they have been exposed to, and if they live in an area where there is a lot of virus being spread.