Skip to main content
King County logo

A COVID-19 self-test is a rapid test that you can do at home and get results within 15-30 minutes. Self-tests are also known as home tests, self-collected tests, or antigen tests. You can purchase self-tests in stores or pharmacies and online.

When to use a COVID-19 self-test

  • If you have symptoms or a close contact or someone in your household is exposed or has COVID-19 symptoms
  • For work or schools (check with your employer/school to see what type of tests they accept)
  • Before or after family gatherings, parties, or holiday functions
  • After large events such as a sports games or faith-based services and after travel

*Do not use a self-test if you are waiting for your test results from a testing site. Wait for your results and follow guidance.

COVID-19 self-tests are not accepted in these situations:

  • To meet travel requirements
  • For entry to establishments requiring proof of vaccination

What should I do if my test is positive?

If you have a positive result, consider yourself positive and:

  • Isolate for 5 days. Continue to wear a mask around others for five additional days after leaving isolation.
  • Tell your close contacts and household members you have tested positive
  • Report test results to Washington State Department of Health by calling 1-800-525-0127 and pressing # (press #7 for Spanish or speak the language you need when the call is connected).

For detailed guidance see our isolation and quarantine page. For resources and support while you isolate, go to kingcounty.gov/nextsteps.

What should I do if my test is negative?

A negative test result means the virus that causes COVID-19 was not found in your specimen. If you took the test while you had symptoms and followed all instructions carefully, a negative result means your current illness is probably not COVID-19.

However, it is possible for a test to give a false negative. You could also test negative if the specimen was collected too early in your infection. In this case, you could test positive later during your illness.

If you have a negative result but are concerned that you might have COVID-19 because you were exposed or have symptoms or you may have a false negative result, then we recommend quarantining yourself and getting another COVID-19 test or performing serial (repeat) testing.

See "What if I have a negative result but I am concerned I have COVID-19" – in General questions #3.

How to use a self-test

For accurate results and for your test to be valid, follow all the instructions inside the self-test box. For additional information about self-testing see the CDC website and resources below:


Questions about self-testing

General questions

If you have a positive result, consider yourself positive regardless of vaccination status and:

  • Isolate for 5 days
  • Tell your close contacts and household members you have tested positive
  • If you have no symptoms, or your symptoms are improving after five days, you can leave your house. If you have a fever, stay home until your fever goes away.
  • You should continue to wear a high quality, well-fitting mask around others for five additional days.

If you use more than one test on a single individual and one of the tests is positive, consider yourself positive and isolate for 5 days.

If you test positive and don't have symptoms and weren't exposed and are concerned this may be a false positive, consider repeat testing for confirmation. Two negative tests in a row are required to confirm a false positive. The tests must be taken greater than 24 hours and less than 48 hours apart. Rapid antigen tests or molecular PCR tests can be used. Rapid antigen tests can be purchased at a pharmacy and a molecular PCR test can be taken a confirmatory test through your healthcare provider or at one of King County's testing sites. Healthcare staff must collect or observe the collection of a confirmatory test. Other than going to get tested you should continue to isolate while awaiting confirmatory results.

For a confirmatory negative test to override a rapid test result, the sample must be collected within 48 hours of the initial positive home-based, self-collected rapid test result.

If you test positive on the confirmation test, continue to isolate from others for 5 days (starting when you initially tested positive or when your symptoms started if you develop symptoms), regardless of your vaccination status.

If you are concerned that you might have COVID-19 because you were exposed or have symptoms, or that you might have a false negative result, then we recommend quarantining yourself and getting another COVID-19 test.

Options for repeat testing include:

  • through your healthcare provider
  • one of the King County testing sites
  • another testing site with confirmatory testing
  • continuing to test (no more than once in a 24-hour period) with a rapid self-test during your quarantine period. This is called serial testing. Serial testing is when a person tests themselves multiple times for COVID-19 on a routine basis, such as every few days. By testing more frequently, you might detect COVID-19 more quickly and could reduce the spread of infection. Some self-administered tests come with more than one test and instructions for performing serial testing. For serial testing to be used as a confirmatory negative test, you must have two negative test results in a row.

If a repeat test is positive, isolate from others for 5 days since your positive test, OR, if you develop symptoms, enter isolation the date your symptoms started, regardless of your vaccination status.

When getting a confirmation test, wear your mask and tell the staff that you have either had a positive test with an at home, self-collected over-the-counter test OR that you have had a concerning exposure or symptoms consistent with COVID-19 BEFORE you remove your mask.

Yes. Some sports are considered high risk for spreading COVID-19, such as water polo, indoor wrestling, basketball and cheer. To reduce the risk of transmission for competitive school-based sports teams, athletes are required to test for COVID-19 three times weekly, including on the day of competition, with a rapid antigen test. Informed consent is required. See full guidance for school-based sports.


Link/share our site at kingcounty.gov/selftest