How do I know that my negative test result is accurate?

Every test has some room for error, known as “false negatives” or “false positives.” Tests that are granted Emergency Use Authorization (EUA) by the FDA must have a certain level of accuracy. There is also the possibility for user error. One way to be more sure about your negative test result is to take a second test at the same time or shortly after your first. A “false negative” could happen if you test too early after exposure to COVID-19; it takes 2-14 days after exposure for COVID-19 to be detected by tests. Testing 3-5 days after a known exposure is the general recommendation.

For those taking at-home tests after being exposed to COVID-19, the FDA now recommends testing multiple times over the course of a few days to ensure that the initial negative test result is accurate. After taking your first at-home test and receiving a negative result, wait for 48 hours and then test again. If it is negative again, then wait another 48 hours to test one final time. If at any point you have COVID-19 symptoms but are still receiving negative antigen test results, you may want to get a PCR-based test from a healthcare provider to make sure of your negative result.

Learn more about diagnostic test accuracy.