NOTE: Federal guidance has not changed on how to test for COVID, and all test kits have specific FDA-approved instructions on how they should be used. This story has been updated to include a recent statement from the FDA surrounding testing.
Could the omicron variant lead to a change in the way we test for COVID?
Federal guidance has not changed on how to test for COVID, and all test kits have specific FDA-approved instructions on how they should be used, but some medical professionals are debating whether or not to add a throat swab to testing methods, particularly with the rise of the omicron variant.
Some medical experts say that with the increase in sore throat symptoms associated with the omicron variant, adding a throat swab, in addition to nasal swabbing, could lead to more accurate test results.
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But the Food and Drug Administration cautions against such advice, particularly for at-home tests.
"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 provided to NBC 5 Wednesday.
The FDA warned, however, of potential safety concerns for self-collection of throat swabs "as they are more complicated than nasal swabs - and if used incorrectly, can cause harm to the patient." The agency added that the Centers for Disease Control and Prevention recommends throat swabs be collected by a trained health care provider.
According to the FDA's testing guidance, which was last updated in December, "different tests are authorized to be used with different types of samples," but the most common sample types include nose or throat swabs and saliva samples.
Dr. Michael Daignault, an ER physician and Chief Medical Advisor for Reliant Health Services, told NBC 5 Tuesday he has seen "some cases where people who do the regular nasal swab test negative."
"But then I've had some doctor friends who started swabbing the backs of throats, and they're finding that's positive," he said.
Some doctors, including Dr. Anthony Fauci, White House chief medical advisor and the top U.S. infectious disease expert, have cautioned that not all at-home antigen tests may be able to adequately detect the omicron variant.
It's a message Illinois' top doctor, Illinois Department of Public Health Director Dr. Ngozi Ezike, echoed last month.
"There are some commercially available tests that won't detect omicron," she said. "But we have to remember that those rapid antigen test, they're not 100%. So if you have symptoms and have a negative test I would still be very cautious."
Preliminary research by the the FDA, in collaboration with the National Institutes of Health's Rapid Acceleration of Diagnostics program, found that rapid antigen tests may be less sensitive at detecting the highly contagious omicron variant and could lead to results that are "false negative."
The research used samples from patients confirmed to be infected with the omicron strain of the virus to study the performance of at-home tests, also known as "antigen" tests.
The agency said early data suggests that antigen tests "do detect the omicron variant but may have reduced sensitivity," meaning it's possible such tests could miss an infection.
Rapid antigen tests, which work by detecting surface proteins of the coronavirus, are relatively inexpensive and quick, with results known in around 15 minutes. They can, however, miss the early stages of COVID-19 infection. Most popular at-home tests advise users to take two tests on separate days to ensure more accurate results.
But Daignault said he believes some of the common symptoms with omicron could play a role.
"I think that's because the omicron variant, we've seen that it's causing sore throat and nasal congestion, and so if you miss a good sample from the nose and you swab the back of your throat, it increases the accuracy of the test," he said.
Daignault noted that such swabs should be taken using the same test.
"What I'm recommending is you take that single swab from that single test and you just swab multiple areas just to increase the overall yield of potential tissue that you're testing," he said.
The recommendation echoes a recent social media trend on Twitter referred to as #SwabYourThroat, which saw users, including a University College London biologist, reporting negative nasal swab tests, but positive results after adding a throat swab.
Multiple experts have reported sore throats and cold-like symptoms associated with the newest coronavirus variant.
Dr. Katherine Poehling, an infectious disease specialist and member of the Advisory Committee on Immunization Practices, told NBC News last month that a cough, congestion, runny nose and fatigue appear to be prominent symptoms with the omicron variant. But unlike delta, many patients are not losing their taste or smell.
The evidence so far, according to Poehling, is anecdotal and not based on scientific research. She noted also that these symptoms may only reflect certain populations.
Still, CDC data showed the most common symptoms so far are cough, fatigue, congestion and a runny nose.
In New York, where cases continue to surge, an ER doctor who became known on social media during the pandemic for his documentation of the battle against COVID, reported breakthrough cases he has seen in those with booster shots experienced "mild" symptoms.
"By mild I mean mostly sore throat. Lots of sore throat," Craig Spencer wrote on Twitter. "Also some fatigue, maybe some muscle pain. No difficulty breathing. No shortness of breath. All a little uncomfortable, but fine."
Cases in people who were fully vaccinated with either Pfizer or Moderna's vaccine, but not boosted, remained mild, but slightly more intense.
"More fatigued. More fever. More coughing. A little more miserable overall. But no shortness of breath. No difficulty breathing," he wrote.
For those with Johnson & Johnson who were not boosted, he wrote the patients "felt horrible," with fevers, fatigue, coughs and shortness of breath, but did not require hospitalization or oxygen.
In the unvaccinated, however, the symptoms were more severe.
"Almost every single patient that I’ve taken care of that needed to be admitted for Covid has been unvaccinated," Spencer wrote. "Every one with profound shortness of breath. Every one whose oxygen dropped when they walked. Every one needing oxygen to breath regularly."
Dr. Angelique Coetzee, the South African doctor who first raised the alarm over the new strain, told the BBC that she started to see patients around Nov.18 presenting with "unusual symptoms" that differed slightly to those associated with the delta variant.
"It actually started with a male patient who's around the age of 33 ... and he said to me that he's just [been] extremely tired for the past few days and he's got these body aches and pains with a bit of a headache," she told the BBC.
The patient didn't have a sore throat, she said, but more of a "scratchy throat" but no cough or loss of taste or smell — symptoms that have been associated with previous strains of the coronavirus.
Coetzee said she tested the male patient for COVID, and he was positive, as was his family, and then said she saw more patients that day presenting with the same kinds of symptoms that differed from the delta variant.
Other patients she had seen so far with the omicron variant had also experienced what she described as "extremely mild" symptoms, and she added that her colleagues had noted similar cases.
Similarly, in the first U.S. case, the president's chief medical adviser Dr. Anthony Fauci said the person was vaccinated but had not received a booster shot and was experiencing “mild symptoms.”
Chicago Department of Public Health Commissioner Dr. Allison Arwady attributed the change to vaccinations, saying that omicron has led to an increase in breakthrough infections, which is leading to more mild illness.
For now, Arwady urged anyone who has a cold to assume it is COVID until testing proves otherwise.
"I would rather people err on the side of assuming right now, with the numbers like they are, regardless of that new symptom, that it is likely to be COVID," she said.