At-home COVID-19 antigen tests detect proteins, called antigens, from the SARS-CoV-2, the virus that causes COVID-19. At-home COVID-19 antigen tests are less likely to detect the SARS-CoV-2 virus than molecular tests, such as polymerase chain reaction (PCR) tests. This is especially true early in an infection or in people who do not have COVID-19 symptoms. This means people should use multiple tests over a certain time period, such as 2-3 days, especially when the people using the tests don't have COVID-19 symptoms.

Over the course of the COVID-19 pandemic, public health scientists have continued to learn about the SARS-CoV-2 virus and the impact of variants on diagnostic tests that detect SARS-CoV-2. Today's recommendations are based on the latest study results from people with likely omicron infection showing that repeat testing after a negative at-home COVID-19 antigen test result increases the chance of an accurate result. COVID-19 diagnostic testing remains a cornerstone of our nation's fight against COVID-19. At-home COVID-19 antigen tests, while not perfect, provide a fast and convenient COVID-19 testing option.
Recommendations:
Before you use a COVID-19 antigen test:
Be aware that at-home COVID-19 antigen tests are less accurate than molecular tests. COVID-19 antigen tests may not detect the SARS-CoV-2 virus early in an infection, meaning testing soon after you were exposed to someone with COVID-19 could lead to a false-negative result, especially if you don't have symptoms. This is the reason why repeat testing is important.
If you plan to use at-home COVID-19 antigen tests, have several tests on hand so you can test more than once. You do not need to use the same brand of test each time for repeat testing.
Be aware the FDA expects similar performance with Point of Care (POC) COVID-19 antigen tests performed at a clinic or doctor's office. A negative POC COVID-19 antigen test result should also be up with repeat testing and an at-home test could be used.
When you use an at-home COVID-19 antigen test:
Follow the test's step by step instructions exactly to perform the test and to read the test's results.
After you use an at-home COVID-19 antigen test:
If you receive a positive result initially or after a repeat test, this means the test detected the SARS-CoV-2 virus and you most likely have COVID-19.
Follow the Centers for Disease Control and Prevention (CDC) guidance for people with COVID-19, including to stay home, isolate from others, and seek follow-up care with a health care provider to determine the next steps.
If you receive a negative result, the test did not detect the SARS-CoV-2 virus at the time of that test.
If you have COVID-19 symptoms, test again 48 hours after the first negative test, for a total of at least two tests.
If you get a negative result on the second test and you are concerned that you could have COVID-19, you may choose to test again 48 hours after the second test, consider getting a laboratory molecular-based test, or call your health care provider.
If you do not have COVID-19 symptoms and believe you have been exposed to COVID-19, test again 48 hours after the first negative test, then 48 hours after the second negative test, for a total of at least three tests.
If you get a negative result on the second test, test again 48 hours after the second test.
If you get a negative result on the third test and you are concerned that you could have COVID-19, you may choose to test again using an antigen test, consider getting a laboratory molecular-based test, or call your health care provider.
If you get a positive result on any repeat test with an at-home COVID-19 antigen test, you most likely have COVID-19 and should follow the CDC guidance for people with COVID-19.
Overall performance of at-home COVID-19 antigen tests
Most at-home COVID-19 tests are antigen tests and do not detect the SARS-CoV-2 virus as well as molecular tests, most of which are laboratory-based such as polymerase chain reaction (PCR) tests. Molecular COVID-19 tests are generally expected to detect the SARS-CoV-2 virus at least 95% of the time when someone is infected. However, at-home COVID-19 antigen tests are generally expected to detect the SARS-CoV-2 virus at least 80% of the time when someone is infected.

When you perform an at-home COVID-19 antigen test, and you get a positive result, the results are usually accurate. However, if you perform an at-home COVID-19 antigen test, you could get a false negative result. This means that the test may not detect the SARS-CoV-2 virus that is in your nasal swab sample. This could happen if you test soon after you get an infection, especially if you don't have COVID-19 symptoms. If you receive a false negative test result, you may unknowingly spread the SARS-CoV-2 virus to others.