CHICAGO (CBS) — The Omicron variant surge is driving a new rush for COVID-19 testing.

As CBS 2 Investigator Megan Hickey reported Tuesday, at-home rapid tests are flying off the shelves. But how accurate are they with regard to the new variant?

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At-home rapid antigen tests look similar to a pregnancy test and give results within 10 to 15 minutes. They are certainly convenient and have been flying off the shelves lately.

But does a negative at-home test translate to worry-free holiday gatherings?

“They’re mostly effective at detecting virus when it’s at the peak of the infection,” said Pablo Penaloza-MacMaster of the Northwestern University Feinberg School of Medicine.

Penaloza-MacMaster, an assistant professor of microbiology-immunology, said there is a trade-off between sensitivity and convenience.

Some makers are claiming anywhere from 85 to 95 percent accuracy. So while not foolproof, a negative result suggests that even if you have a low amount in your system, you’re not very contagious.

“That test that you buy at the pharmacy gives you a one-day pass,” Penaloza-MacMaster said.

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Just last week, Chief Medical Adviser to the President Dr, Anthony Fauci said some preliminary information shows that not all tests will accurately test for Omicron. This prompted
several test makers to announce that they’ve been able to detect it.

“There’s got be a point where it could override some of the tests, so that’s an accurate assessment,” Penaloza-MacMaster said. “But as of now what we know is that most tests that are being sold in the pharmacies are still working.”

So while the rapid tests can deliver an extra level of comfort this holiday season, Penaloza-MacMaster stresses that there’s a much more foolproof option for protection.

“I’m going to say that that third booster that third those is what we need to do for the holidays,” he said.

Penaloza-MacMaster said many of the test kits come with two tests because they encourage serial testing, which can help improve accuracy of your results.

The at home tests range between $20 to $40, but many stores are cautioning that you call ahead.

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As we found Tuesday by surveying CVS and Walgreens locations across the city and the suburbs, inventory at many stores right now is pretty hit or miss.

Megan Hickey