How to ensure accurate results from at-home COVID tests being sent by federal government

The federal government’s website to order free at-home COVID-19 test kits went live Tuesday.

The website is part of President Biden’s promise last month to deliver millions of free tests directly to Amercians' homes as the omicron variant surges. 

You can order the tests through or There is a limit of four tests per household. Tests can also be ordered by calling 1-800-232-0233.

A lot of people bought at-home tests during the holidays, but doctors said there are a few things to know before you swab again. 

"The at-home tests are rapid antigen tests. They come with a set of instructions that are really important. The most important part of having an accurate rapid antigen test is to have a good sample," said Dr. Michael Teng, a USF Health virologist.

Scientists said the at-home tests are appealing because the results come back fast, but following the instructions is critical for accuracy. Dr. Teng said the results are pretty accurate, especially if you have symptoms.

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He said it's important to follow the directions exactly and to use both provided tests at the instructed intervals.

"These rapid antigen tests are not the most sensitive tests that we have. So it's very possible that you're negative one day and positive the next day," said Teng.

UF Health’s epidemiologist Dr. Cindy Prins said it matters when you decide to use a test. 

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"So I know some people are using these tests because they want to check whether or not they're infected with COVID 19 before they go to an event, where to go, visit a person or something like that. They're not necessarily going to be as accurate if you are without symptoms and are just kind of using it to screen yourself," said Prins. "So what we tell people is if you're testing under those circumstances, test more than once."

Health experts said to wait at least three days after exposure to test for the virus.

"If you test positive with an at-home test, you really should follow up with your local health department and report that positive result. And that's because they're going to be able to guide you on how long you should stay under isolation," said Prins.

Public health experts say the at-home tests are great especially if you’re pressed for time. If you want to confirm the results, there are also PCR tests that take a day or two days to come back.