Confirm and deny Cadham Provincial Laboratory staff 'the silent firefighters of disease'
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Hey there, time traveller!
This article was published 15/04/2020 (1618 days ago), so information in it may no longer be current.
In a boxy, nondescript building tucked away in the corner of the Health Sciences Centre campus, staff at Cadham Provincial Laboratory are using cutting-edge machines to probe a microscopic killer.
Behind its doors, which only those with special clearances are allowed to enter, staff have tested more than 18,000 samples for COVID-19 in the past month, a number ramping up by hundreds every few days.
“There’s a team here that’s always on watch for Manitobans,” lab director Paul Van Caeseele told the Free Press.
He explained by phone Thursday the daily process that had staff working around the clock.
“The morale, strangely enough, is quite positive. This is what they came to work for Cadham for,” he said.
Testing sites around the province send samples to the lab in plastic tubes with a liquid that stabilizes the virus. Known as a viral transport medium, most are a nasopharyngeal swab taken from deep inside the nose, but Cadham also accepts throat swabs and vials of coughed-up sputum.
The front-end staff check those samples for any leaks, such as when a cap was screwed on the wrong way, and if the name on the printed requisition document matches the one on the tube.
A very small number are cancelled on those grounds, and a request is sent asking for the person to re-tested.
The rest get a matching barcode sticker for the paperwork and the sample.
As data-entry clerks type the requisitions into a database, the medical-laboratory technologists get a rack of test tubes, which are sorted by priority.
Cadham gives and takes COVID-19 research
wfpsummary:Staff at the Cadham Provincial Laboratory are supporting national research efforts, while keeping abreast of constant developments through Winnipeg’s health network.
Before Health Canada approved the portable Spartan testing kit this week, the National Microbiology Lab gave one of its four kits to Cadham staff, to verify if known results were replicated by the new device.:wfpsummary
Staff at the Cadham Provincial Laboratory are supporting national research efforts, while keeping abreast of constant developments through Winnipeg’s health network.
Before Health Canada approved the portable Spartan testing kit this week, the National Microbiology Lab gave one of its four kits to Cadham staff, to verify if known results were replicated by the new device.
Cadham lab will also soon help with testing for antibodies in the blood of people who have survived COVID-19, which might help treat infected people or even prevent transmission.
“There are a lot of products flooding the market which really do not look reliable. But a couple of the ones that do look more reliable we’ve arranged to get ahold of,” said Cadham medical director Paul Van Caeseele.
Of the lab’s roughly 120 employees, he estimated about a dozen Cadham staff are helping with those efforts on a part-time basis.
Van Caeseele also said researchers at the University of Manitoba and the Health Sciences Centre are constantly exchanging information with Cadham staff on the latest global research on the coronavirus.
— Dylan Robertson
Specimens from hospital patients and health-care workers get tested immediately, in individual tubes.
Meanwhile, samples from specimens taken from the general public and returning travellers are combined into a single tube — currently four at a time. If that tube tests positive, the remainders of those four original specimens are then tested individually.
“It allows us to tell people they’re negative faster. It’s a little slower on the positive side, but now we know whom we need to focus on,” said Van Caeseele.
Cadham tests the samples through a mix of semi-manual and automated methods.
Lab staff designed the manual method at the start of the year, based on instructions from the National Microbiology Laboratory and on advice from the United States Centers for Disease Control and Prevention and the World Health Organization.
The first step is called extraction. Chemicals called reagents strip away mucus and external parts of the coronavirus, leaving just the "genetic fingerprint," called the RNA.
“That kind of peels away the garbage and leaves just the virus behind," he said. "The purer the sample, the less likely you run into the test not working, or invalid results.”
A device called a real-time thermocycler creates a polymerase chain reaction, which is when the genes are doubled about 40 times, creating roughly a trillion copies of the gene.
A probe sits near the sample, coated with a reagent that creates trace amounts of light as the specific gene for COVID-19 is detected.
This enzymatic reaction is detected by a device called a fluorometre, which measures the slightly yellow-green wavelengths.
“Once we (measure) enough of that light, then we say it’s positive,” said Van Caeseele.
False-positives explained
Manitoba’s Cadham lab has had some tests come back positive before they were confirmed as negative. Medical director Paul Van Caeseele believes these were caused by two situations.
Trace amounts of RNA can show up so weak that tests can’t actually confirm whether a patient contracted COVID-19, possibly because the patient had nearly recovered by the time the test was taken.
Earlier on, Van Caeseele said there were “a couple of instances” where a sample came up inconclusive. The tube sat next to a very strong sample on the rack, suggesting “a tiny bit of splash-over,” which can happen with some viruses.
“We know how to investigate those now, and those false-positives don’t happen anymore,” he said.
A few times, samples have shown no genetic material (neither DNA or RNA), suggesting the swab didn’t go deep enough, at which point the lab asks the testing centre to get another sample from the patient.
— Dylan Robertson
Much of that process has been expedited though machines called commercial platform kits; Cadham uses two machines that can handle nose swabs and runs about 96 samples at a time, putting the results directly into the lab software.
Cadham gets results within 48 hours, often the same day.
Last month, a reagent shortage capped testing at roughly 200 samples a day, but the lab now has enough chemicals and machines to process as many samples as it gets, Van Caeseele said.
Cadham undergoes daily quality-control tests, which include running samples that are already known to be positive and negative, to make sure both machines and the scientists involved in the manual process are both giving accurate results.
About two weeks ago, National Microbiology Lab staff certified Cadham’s methodology, meaning samples no longer have to be sent around the corner to the federal lab for a confirmatory test.
After the testing, staff put the swabs and vials into a device resembling a washing machine, which renders the materials, heating them to the point of killing the virus.
“An enormous autoclave cooks the baloney out of it,” Van Caeseele said, adding that the material is then put in a hazardous-waste landfill.
“COVID has put a spotlight on us, and I have to say everybody in this lab has stepped up and done their job above and beyond the expectations that I have had.”
He has led the lab since 2000, but rarely gets interview requests, which he takes as a sign of things running well.
“We’re like the silent firefighters of disease.”
dylan.robertson@freepress.mb.ca
History
Updated on Thursday, April 16, 2020 11:09 PM CDT: Fixes typo
Updated on Friday, April 17, 2020 11:08 AM CDT: Cutline fixed.
