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5 quick questions about rapid COVID-19 tests

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COVID-19 testing is an important tool in the fight against the pandemic. Rapid antigen tests give quick results and are easy to use. And they are widely available.

So what exactly are they? Here are answers to some common questions about the tests, with information from the Centers for Disease Control and Prevention, the U.S. Food and Drug Administration and other experts:

Q. What is a rapid antigen test?

A. It's one type of COVID-19 test. It can show if you are currently infected with the coronavirus. It doesn't show if you had COVID-19 in the past.

Rapid tests look for a specific protein (antigen) from the coronavirus in mucus from your nose or throat. Most rapid tests use a nasal swab to collect the sample.

Q. How fast do you get results?

A. Rapid antigen tests give results in 15 to 30 minutes. That's a big advantage over many molecular tests, for which it may take days to get results from a lab.

Q. When are they useful?

A. Because they show results quickly, rapid tests can be beneficial when you have COVID-19 symptoms or think you might have been exposed to the coronavirus. You can know within minutes if you should isolate yourself from others as a precaution or get further COVID-19 testing.

Q. What are the drawbacks?

A. Rapid antigen tests work best when you have COVID-19 symptoms. Often, that's when there is more of the virus in your body to detect. So if you don't have symptoms and you take a rapid antigen test, you have a higher chance of getting a false negative result. The test may say you don't have the virus when you really do.

That's why your doctor may want you to follow up with a molecular test if your antigen test comes back negative, especially if you have symptoms.

In general, if your rapid test result is positive, it means you likely have COVID-19 and should isolate. But your doctor may want to confirm these results if you haven't been around someone with COVID-19.

Q. Where can you get a rapid test?

A. You can get a rapid COVID-19 test from your doctor, from your local health department, in some stores or online. If you do the test yourself, be sure to follow the instructions that come with the kit. Then follow up with your doctor about the results.

For more helpful tips on COVID-19, check out our Coronavirus health topic center.

Reviewed 4/30/2023