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  1. Coronavirus (COVID-19) and Medical Devices

At-Home COVID-19 Diagnostic Tests: Frequently Asked Questions

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Diagnostic tests can show if you have an active COVID-19 infection and need to take steps to quarantine or isolate yourself from others.

This page supplements the information found at: At-Home OTC COVID-19 Diagnostic Tests and provides answers to frequently asked questions related to at-home COVID-19 diagnostic tests. This page is part of the FAQs on Testing for SARS-CoV-2.

Q: When should I test for COVID-19?

A: COVID-19 testing is important to find out if you have COVID-19 so that you can get treatment, if needed, as well as to be aware if you are infected and should stay away from people to help reduce the spread of the virus. You should test for COVID-19 in the following situations:

  • If you have symptoms, test immediately, and then test again per the instructions if your first result is negative.
  • If you were exposed to someone who has COVID-19 and you do not have symptoms, wait at least 5 full days after your exposure before testing. If you test too early, you may have an inaccurate result.
  • If you are in certain high-risk settings, you may need to test as part of a screening testing program.
  • Consider testing before coming into contact with someone who has a high risk for severe COVID-19, people who are older adults or immunocompromised, or have other medical conditions, especially if you are in an area with a medium or high COVID-19 Hospital Admission Level.

Q: What do my at-home COVID-19 test results mean?

A: If you receive a positive result on any COVID-19 test, assume you have COVID-19. Be sure to follow the CDC's guidelines for people with COVID-19, including to stay home, isolate from others, and seek follow-up care with a health care provider to determine what steps to take next.

If you receive a negative result on your at-home COVID-19 antigen test, it means the test did not detect the virus that causes COVID-19, but it does not rule out an infection because some tests may not detect the virus early in an infection. Always do a repeat test 48 hours after a negative result on an antigen test. The FDA encourages you to voluntarily and anonymously report your positive or negative test results every time you use an at-home COVID-19 test. You can send your test result to MakeMyTestCount.org or use an app or other digital option for self-reporting that may be included with your test.

Find out more about at-home testing, when and how often to test, and understanding your test results at Understanding At-Home OTC COVID-19 Antigen Diagnostic Test Results.

Q: I got a negative test result on an at-home COVID-19 antigen test. Do I need to take another test?

A: Yes. The FDA recommends repeat testing following a negative COVID-19 antigen test result whether or not you have COVID-19 symptoms. COVID-19 antigen tests are less accurate than molecular tests and may not detect the SARS-CoV-2 virus early in an infection or in people who do not have COVID-19 symptoms.

You should perform repeat testing following a negative result on a COVID-19 antigen test to reduce the risk an infection may have been missed (false negative result) and to help prevent unknowingly spreading the SARS-CoV-2 virus to others.

  • 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 do not have COVID-19 symptoms, 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 positive result on any COVID-19 test, you most likely have COVID-19 and should follow the CDC guidance for people with COVID-19.

In August 2022, the FDA issued a Safety Communication on the need to perform repeat testing to reduce your risk of a false negative result. In November 2022, the FDA required all manufacturers of EUA-authorized COVID-19 antigen tests to update their labeling to reflect the need for repeat testing at least twice over three days for individuals with symptoms of COVID-19 and at least three times over five days for individuals without symptoms of COVID-19, as appropriate based on their authorized uses.

Q. Do I need to report my at-home COVID-19 test results?

A. The FDA encourages you to voluntarily and anonymously report your positive or negative test results every time you use an at-home COVID-19 test. You can send your test result to MakeMyTestCount.org or use an app or other digital option for self-reporting that may be included with your test. Report each test result one time.

The data from MakeMyTestCount.org can help public health departments know how fast the virus is spreading. This valuable test data helps public health departments assess and modify their response to COVID-19 in their local communities, states, or across the country. The MakeMyTestCount website is developed through the National Institutes of Health (NIH) Rapid Acceleration of Diagnostics (RADx) Tech program and allows consumers to anonymously report their test results from OTC at-home COVID-19 test.

Q. Are at-home COVID-19 tests safe to use? Do they contain toxic chemicals?

A: FDA-authorized at-home COVID-19 tests are safe to use when people follow the manufacturer's step by step instructions. However, incorrect use of at-home COVID-19 tests can cause harm if the parts of the test kit, such as liquid solutions in small vials that may contain chemicals like sodium azide, are swallowed or if the liquid solutions touch a person's skin or eyes. The FDA has provided recommendations to promote the safe use of at-home COVID-19 tests in a Safety Communication issued March 18, 2022, including to keep all parts of at-home COVID-19 tests out of reach of children and pets before and after use, and to follow the test's step by step instructions exactly, including the Warning, Precautions, And Safety Information.

Q: Can I use an authorized at-home COVID-19 diagnostic test if it was left outside in freezing temperatures or in the heat?

A: Since shipping conditions may vary, test developers perform stability testing to ensure that the test performance will remain stable when tests are stored at various temperatures, including shipping during the summer in very hot regions and in the winter in very cold regions.

However, test performance may be impacted if the test is used while it is still cold, such as being used outdoors in freezing temperatures or being used immediately after being brought inside from freezing temperatures, or in a hotter than expected environment, such as outside in the summer. The stated performance generally assumes the test is being performed in an environment that is between 15-30⁰C (approximately 59-86⁰F). The specific conditions that were validated are included in the authorized Instructions for Use for each test.

In order to ensure appropriate test performance with a test that is delivered to you in below freezing temperatures or in very hot temperatures, you should bring the package inside your home and leave it unopened at room temperature for at least two hours before opening it. Once the package is at room temperature, you may open it and perform the test according to the authorized instructions for use. As long as the test line(s) appear as described in the instructions, you can be confident that the test is performing as it should. If the line(s) do not appear in the correct location(s) and within the correct time as shown in the test instructions when you perform the test, then the results may not be accurate, and a new test is needed to get an accurate result.

In addition, long exposure to high temperatures may impact the test performance. If your test has been left in a high temperature environment beyond the normal shipping time to be delivered to you, such as being left outside in the heat for several days, the FDA recommends considering using a different test.

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