COVID at-home testing is for nasal passages alone.

People who know what they’re talking about say COVID at-home testing is for the nose, not the throat. People in the U.S. are having a hard time getting their hands on at-home rapid tests because of the fast-moving omicron variant, which leads to more than half a million new COVID-19 cases every day.

People who have COVID variants, like omicron, may have virus particles in their throats before they reach the nasal passages where test swabs are done. Rapid tests in general may not be as good at catching the new variant as they claim. For extra protection, some people put a swab in both the back of their throat and their nose.

But federal agencies and health experts say that COVID at-home testing should be used as directed and not to add a throat swab – at least, not yet – to the tests. A throat swab may be needed in the future, but the tests that the US currently has aren’t made to detect viruses in a person’s throat and could give false results.

I like that people can use these tests however they want to. That’s the idea of “COVID at-home testing,” isn’t it? That’s what Dr. Emily Volk, who leads the College of American Pathologists in the United States, told me. There is a test that they need to take, tho. “The FDA does not allow them in any other way.”

It became more popular after the Food and Drug Administration said last week that rapid antigen tests may not be as good at detecting the omicron variant of the virus as they were before.

The FDA warned people about the dangers of rapid antigen testing. Then, on Wednesday, a preprint study got a lot of attention on social media and raised more questions about it.

As part of a study that hasn’t been peer-reviewed, the study tracked 30 people in New York and California who were tested every day. They were tested with saliva and nasal swabs for polymerase chain reaction (PCR) tests and for rapid antigen tests. All of the antigen tests gave false-negative results, and 28 of the 30 people had enough virus to spread it to other people.

Doctor Michael Mina, who is an infectious disease expert and worked at Harvard for years, says the study’s findings don’t show that rapid antigen tests can’t detect omicron. He is the chief science officer of the testing company eMed.

Tests show that they can find virus particles in saliva before they can find them in the nose.

Does that mean we have to throw away our nasal swabs as a way to get rid of the virus? Not at all, said Mina, an outspoken advocate for rapid testing to stop the spread of viruses. “However, it looks like it starts transmitting at low viral loads before the virus grows big enough to get into your nose.”

Swabbing your throat is a risky thing to do, says Dr. Michael Blaivas, chief medical officer of a company that makes diagnostic technology.

Virus particles are most concentrated in the oropharynx, which is the part of a person’s throat at the back of their throat. An ordinary nasal swab can’t reach this area.

Because not enough virus was collected, if you don’t go to the area, you might get a false negative result.