FEB. 2 UPDATE TO THIS STORY:

COVID-19 test collection sites say some individuals are showing up unprepared for the more comfortable saline gargle test which means they can’t use the alternative to nasal swab testing.

Those who want COVID-19 saline gargle device must avoid eating, drinking, vaping or smoking, brushing their teeth or chewing gum for at least one hour prior to taking this test. Otherwise, the test won’t yield an accurate and reliable result.

The test is done by swishing and gargling saline water in the mouth for 30 seconds under the supervision of a test administrator.

It is currently available at 14 test collection sites across urban and rural Vancouver Coastal Health communities. It accounts for just over 30% of all COVID-19 tests performed in the region. Test collection sites are listed on the VCH website.

The BCCDC has published a simple video guide for parents and caregivers to show how they can practice with their child, before they arrive at a COVID-19 test collection site. A video with guidance for adults has also been created. VCH advises waiting at least two hours between practicing and doing the actual test collection to avoid affecting test results.

Here’s a story about how the testing was developed:

 

BY PAMELA FAYERMAN

Not long after the pandemic began, it became apparent the supply of swabs required for collecting nasopharyngeal (NP) samples could become insufficient because of global demands and inadequate supply chains.

Experts also identified other issues with the long swabs. They can be uncomfortable and even traumatic for some, not to mention they pose a risk to healthcare technicians testing individuals because the probes can provoke gagging and coughing in those being tested.

In July, this website reported on the growing global shortage of nasal swabs and preliminary research being done around the world on less invasive saliva sampling showing comparable accuracy to swab tests.

Officials at the B.C. Centre for Disease Control followed the work being done elsewhere and three months ago, became one of the first jurisdictions in the world to introduce a saline rinse-gargle method for COVID-19 testing. The saline gargle was initially introduced as an alternative to nasopharyngeal (NP) swabs for school-aged children. But last month, it became available to adults as well.

The testing is done by swishing and gargling salinated water and then spitting it into a tube.

In the current BC Medical Journal, four provincial experts discuss the work that led to this point.

Dr. David Goldfarb

Meghan McLennan, of Provincial Laboratory Medicine Services; Dr. David Goldfarb, MD, a Medical Microbiologist who is associate head of the Department of Pathology and Laboratory Medicine at BC Children’s & Women’s Hospitals; Michael Donoghue of the UBC Centre for Disease Control; and Dr. Linda Hoang, a Medical Microbiologist and Associate Director of the BCCDC Public Health Laboratory, state:

“Saliva was the most common swab-independent alternative at the time; however, some patients struggle to provide an adequate volume, and saliva is a difficult specimen type for laboratories to handle. Also, the mucoid nature of saliva was not ideal for the laboratory and required additional processing steps for the sample to be polymerase chain reaction (PCR) ready.”

They scanned medical literature and found “limited and vague” reports of mouthwash-type samples for testing other viruses. They identified saline gargle as a highly possible option.

“Laboratory testing of PCR performance, stability, and appropriateness of the saline gargle was evaluated. Saline gargle performed well compared to the standard nasopharyngeal swab and viral transport media system.”

The validation process was done at BC Children’s Hospital where children getting COVID-19 testing had NP swabs, saline gargle, and saliva specimens. The validation showed test results were equivalent for the NP swab and saline gargle, while saliva had lower clinical sensitivity, especially in children. As well, children ranked the saline gargle collection as the preferred method.

The next step was a province-wide study involving all COVID-19 testing laboratories to confirm that saline gargle specimens were compatible with all COVID-19 nucleic acid-based testing platforms. The validation exercise ended just as schools were ramping up to accept students back, timely because everyone recognized that in-person learning would mean more children would require COVID-19 tests.

“Testing by collecting an NP swab can be traumatic for children, parents, and health care workers, but using the less-invasive saline gargle helps to lessen barriers to testing,” the authors note.

The provincial implementation started a week after children returned to classrooms.

Online videos and instructions were created. Parents are advised they must practice the technique with their children at home with a solution of salt and water. “This is especially important for young children who, initially, often immediately spat out the saline solution because of its saltiness. If that happens, individuals must either wait two hours before trying the saline gargle again or get tested with the NP swab.”

There are important instructions for anyone seeking the newer tests:

  • You cannot eat, drink, vape, smoke, brush your teeth, or chew gum for at least one hour before taking the test.
  • If you want to use the mouth rinse and gargle test, you must review the information on this page first.

The authors say that their work has helped jurisdictions across Canada and abroad adopt the saline gargle method in their regions.

This is knowledge translation at its best.

Read the BCMJ article here.

Locations of the 110 COVID-19 test collection sites in B.C.

pamela@medicinematters.ca