Researchers from Western University and Lawson Health Research Institute in London, Ont. are sounding the alarm on COVID-19 testing techniques across the country, saying most instructions for conducting nasal swabs are incorrect.
The research could have far-reaching implications for testing in Canada throughout the pandemic.
“They just don’t go deep enough into the nasal cavity,” said Dr. Leigh Sowerby with Western and Lawson in a release.
The team led by Sowerby found that there are wide discrepancies in the instructions for how deep the swabs used for COVID-19 are to be inserted in Canadian noses.
Sowerby, who is an expert in the anatomy of the head, neck, and nose, said he was surprised to find most instructions in Canada are not effective.
His team analyzed the COVID-19 testing instructions provided by provincial and territorial authorities and found that there were wide variations in technique.
Their full findings were published in the Journal of Otolaryngology – Head & Neck Surgery.
Sowerby along with Dr. Breanna Chen made a video to demonstrate just how far a swab should be inserted into a nose to reach the top of the throat behind the nose, known as the nasopharynx.
Swabs that reach this cavity are shown to be the most accurate for COVID-19 and are considered the gold standard.
However, the team’s research found that less than a quarter of health instructions across the country tell those doing the tests to swab deep enough to the reach cavity.
“If we are doing what we are calling a nasopharyngeal swab, the technique for that should be standardized; there is no reason why there should be so much variability,” Sowerby said.
Six provinces and territories, including the Northwest Territories, Nunavut, Ontario, Saskatchewan, Prince Edward Island and Alberta, recommended that the swab be inserted to a depth of four centimetres which does not reach the nasopharynx.
British Colombia and Manitoba recommend seven centimetres which is still not deep enough.
Nova Scotia, Newfoundland, New Brunswick, and Yukon were the only provinces and territory to suggest a far enough distance.
“The take-home message is that if we want the most accurate test results, there is room for improvement in the test instructions,” said Sowerby.