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Q: Are at-home COVID tests reliable?

If you’re having symptoms or think you may have been exposed to COVID, and you can’t get to your doctor for testing, an at-home test can be a convenient option. But how reliable are they? The answer depends on the kind of test you use -- and if you use it correctly.

At-home tests, also called self-tests, are COVID-19 test kits that are available without a prescription. There are two types of tests: PCR tests, and rapid antigen tests. With PCR tests, you collect a sample at home (nasal swab or saliva), mail it to a laboratory for analysis, and get the results within a few days. With rapid antigen tests, you can get results in as little as 15 minutes.

The PCR test takes longer, but it is more sensitive. That means it can usually tell if you have COVID even if you’re early in the illness and only have a small amount of virus in your system. It’s also more accurate -- it is much less likely to give you a false result.

Rapid antigen tests are less accurate and sensitive. It’s possible to get a false positive, where the test shows you have COVID even if you do not. It’s also possible to get a false negative. And the test may not detect COVID if you’re not having symptoms. This can give you a false sense of security.

That doesn’t mean rapid self-tests aren’t useful. Rapid tests can give you quick feedback on what you should do next. If you’ve been exposed to COVID or you’re having suspicious symptoms, getting a positive result can confirm you should self-isolate and call your doctor. A negative test means you should continue to take precautions and confirm your results with a PCR test.

Finally, if you do decide to use an at-home test, be sure to read the instructions and follow them carefully to get the best results.

The best thing to do if you’re having COVID-like symptoms or have been exposed to someone who is COVID-positive is to get tested. On Maui there are testing sites and clinics located all over the island - you can find a comprehensive listing at www.mauinuistrong.info. If you cannot get an appointment for a test, you can use an at-home test but be sure to follow up with your doctor whether you have a positive or negative test result.

Michael J. Shea , MD

Critical Care Medicine

Maui Memorial Medical Center
221 Mahalani Street
Wailuku, HI 96793