With gold standard tests for COVID-19 becoming increasingly difficult to find, the debate revolves around whether to collect a throat swab sample along with a nose swab for rapid testing at home, against some instructions on the package.
For most tests, the accuracy of a combined nose and throat swab has not yet been tested, and the official Canadian and US health guide still advises people to follow the kit’s user instructions that have on hand.
However, a debate has emerged on social media and among some experts after anecdotal evidence from people who said they only tested positive after rubbing the back of their throat and nasal cavity, despite the test instructions. of rubbing only the nose.
“I finally took the advice of Twitter and took a swab from my throat and nose,” wrote Jennifer Rohn, a British cell biologist. in a tweet on December 27. “If you think you might have COVID, consider adding the throat swab.”
The the advice was echoed by Dr. Michael Mina, a noted US epidemiologist, who wrote that Omicron infection could be detected first in the throat due to its shorter incubation period compared to other variants, and a throat and nasal swab can improve the chances of get an infection.
Others have pointed out a South African pre-printed study, which found that nasal polymerase chain reaction (PCR) missed 14 percent of Omicron’s cases, compared to saliva swabs that successfully detected all cases.
Official orientation of Health Canada and Ontario Public Health, as well as a recent statement from the United States Food and Drug Administration (FDA), holds that a nasal cavity swab is the best standard to follow when it comes to testing for COVID-19 at home if the package indicates it.
“The FDA has noted safety concerns regarding self-collection throat swabs, as they are more complicated than nasal swabs and, if used incorrectly, can cause patient harm.” a statement provided to the media by the FDA said. “The [U.S. Centers for Disease Control] recommends that a trained healthcare provider collect throat swabs. ”
Christine Bruce, senior director of the laboratory medicine program at University Health Network in Toronto, said that laboratory employees continue to follow Health Canada’s guidelines on using a nasal swab only when performing a rapid antigen test, as There is no definitive research to suggest a throat swab in conjunction with a nasal swab would yield a more accurate result.
“Our position as laboratory experts would always be to follow the manufacturer’s and Health Canada’s instructions,” Bruce said.
While the throat swab collection method is not used in the United States or Canada, it is officially approved in the United Kingdom, where certain rapid tests distributed by the National Health Service Instruct collection of nasal and throat swabs. Others that are shipped, such as the FlowFlex or Orient Gene rapid tests, instruct users to take only one nasal swab.
For tests that take samples from the throat, UK and testing guidelines advise users not to eat or drink for at least 30 minutes prior to testing.
Dr Tara Kiran, a primary care physician at Unity Health Toronto, said it’s important to note that experts and clinicians are still in the process of learning how to best use rapid home tests to detect Omicron. But he added that his advice is to take samples from both the nose and throat to get more sensitivity from the test results.
Kiran also said that he agrees with the FDA that there could be a risk of doing a throat swab incorrectly without package directions, but easy-to-follow resources and videos are available at How to Safely Perform a Combined Nose and Throat Smear at Home.
Although not as accurate as the gold standard polymerase chain reaction (PCR) test due to a greater margin of error, rapid home tests have become the best option for most people to determine whether they are sick or not, as Ontario’s PCR testing capacity has increased. been limited due to an increase in cases linked to the Omicron variant.
But if someone is developing symptoms, Kiran advises that they isolate themselves regardless of a negative or positive result, as rapid tests are not entirely accurate.
“A rapid antigen test does not guarantee that you cannot transmit the virus at this time or that you do not have it, because it could be early and the [infection] it’s not showing right now, ”Kiran said.
Reference-www.thestar.com