By Brooke Rogers

DALLAS (CBSDFW.COM) – If you can get your hands on one, at-home rapid tests have become an important tool in determining if you have COVID. But can you trust the results?

There are multiple brands sold in multiple places…

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“You can buy them at Walmart. You can buy them on Amazon. They’re pretty easy to use,” said Dr. Donna Casey, Internal Medicine Specialist at Texas Health Dallas.

Dr. Casey said the tests are generally pretty accurate – as long as you follow a few simple tips. First, read the directions.

“I think some of the biggest mistakes that people make are not putting the swab into their nose far enough or not putting it in long enough,” said Physician’s Assistant Julie Mitchell.

The swab needs to go around 3/4 of an inch inside each nostril for 15 seconds, spinning it 5 times.

“These swabs don’t need to go all the way up to your brain to be accurate,” Mitchell said.

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Then you place the swab in a dropper, put several drops of the solution onto a test card, and wait. Another mistake?

“Not waiting long enough to read the results of the sample and also waiting too long,” she said.

But Casey said the top factor in false results is testing too soon. She said not to test until three days after exposure unless you have symptoms.

“So what we’re actually doing is wasting tests, because you’re not going to test positive for two to three days,” she said.

She suggests testing on days three and four. If the results are still negative and you have no symptoms, she said you should still mask, especially around those who are vulnerable.

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Casey said we will likely still be relying on these tests for at least a few more weeks. According to projections by UT Southwestern, cases won’t peak until the end of January.