Are you doing that COVID test wrong? Experts debate where to stick swab

Coronavirus

(NEXSTAR) – Many Americans are relying on at-home COVID-19 tests to determine if that scratchy throat and stuffy nose is the omicron variant, a cold, or something else entirely. But as complaints surface that the tests are slow to pick up on the highly contagious variant, advice is spreading on Twitter suggesting you should be taking that at-home COVID test a little differently.

Some biologists, doctors and epidemiologists have said swabbing your throat in addition to your nose (using the same swab) could help detect a positive COVID case more accurately and earlier.

Dr. Bob Wachter, the chair of medicine of the University of California, San Francisco’s medical school, shared one such anecdote Saturday. Wachter’s 28-year-old son was sick with COVID symptoms, he said, so Wachter went over to give him a test.

“Local pharmacies were all out of rapid tests, but I had one set stashed away. He came outside (I wore an N95) & we ran it, w/ a nasal swab. It was negative,” Wachter tweeted.

“I wondered if he’d be an example of the newly reported problems with false-negative rapid tests in the first days of an Omicron infection,” the doctor continued.

Wachter had seen reports that taking a saliva sample may help detect the virus sooner, so he went back the next day and swabbed his son’s tongue and tonsils first, then stuck the stick up his nose – “a little gross,” he admitted.

The results were positive.

Was it the fact that the test was taken a day later or that it included saliva (or something else) that changed the results? There isn’t peer-reviewed science to back up what Wachter and others are doing, but there is anecdotal support from at least a few doctors.

Eric Feigl-Ding, prominent epidemiologist and former Harvard Medical School professor, advocated for the saliva swabbing method for omicron and told the Washington Post it was supported by a “confluence of data.”

Michael Mina, also an epidemiologist and Harvard Medical alum, explained on Twitter: “Virus may start further down. Throat swab + nasal may improve chances a swab picks up virus.”

Israel’s health ministry is already directing people to swab their throats along with their noses when using the testing kits, Reuters reports. The U.K.’s Health Security Agency created a tutorial video on YouTube showing how to take the combined sample.

There’s also one small study, that hasn’t yet been peer reviewed, of 29 people in New York, Los Angeles and San Francisco with the omicron variant of COVID. It found PCR tests of saliva samples were able to detect the virus about three days before antigen tests on nasal samples.

But until there’s peer-reviewed science, the Food and Drug Administration’s stance remains the same: stick to the instructions.

“The FDA advises that COVID-19 tests should be used as authorized, including following their instructions for use regarding obtaining the sample for testing,” the agency said in a statement to the the Post, citing concerns people could hurt themselves by using the kits incorrectly.

Nam Tran, the professor who runs COVID-19 testing at UC Davis Health, told BuzzFeed News something like food residue in your throat or mouth could throw off the results, too.

Also, it’s unclear how accurate at-home tests are when done with a throat swab, because it hasn’t been systematically tested.

Some testing sites run by local health departments, hospitals, clinics and private companies have made the switch to collecting saliva samples or a throat swab instead of the up-the-nose swab we’ve grown familiar with (for better or for worse).

No matter how you take the sample, experts remind people that a test result offers limited information even when done correctly: whether or not the virus is detected in that sample at that time. To get the most complete idea of whether or not you’re infected, you need to test regularly. For the most accurate results, seek out a PCR test when possible.

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