The recent recall of Canada’s first rapid point-of-care test device highlights the importance of laboratory testing capacity to handle the anticipated colossal effort required to trace and test suspected COVID-19 infections during a so-called re-opening of social and economic activity.
“We’re still a long ways from point-of-care testing (POCT) replacing real-time PCR (polymerase chain reaction) — at least in this current iteration” of responding to the coronavirus pandemic, asserts Christine Nielsen, chief executive officer of the Canadian Society for Medical Laboratory Science, the national certifying body for medical laboratory technologists and medical laboratory assistants.
Technologists, at least for now, said Nielsen, are effectively the gatekeepers of testing the world over. Until a rapid testing device can be widely distributed, technologists are the only ones who can process bulk tests accurately.
Whereas a POCT for COVID-19 is the “holy grail,” lab tests remain the “gold standard,” says Nielsen.
On April 11, Health Canada approved the first Canadian rapid test device by Spartan Bioscience, which said, “The automated test can be operated by non-laboratory personnel in settings such as airports, border crossings, doctors’ offices, pharmacies, clinics and remote communities.”
Spartan claims one device, branded “The Cube,” can process one test in under an hour whereas one PCR lab device can screen 1,056 swabs in eight hours — as in the case of Roche, a company that supplies Canadian labs with test equipment.
Tens of thousands of Spartan’s units were to have been ordered and delivered to various provinces.
However, on May 3, the company said it voluntarily recalled its product after Health Canada raised concerns about the swab.
“Spartan has shipped 5,500 tests nationally for validation to provincial and federal government health agencies,” the company said. “Spartan will be working as quickly as possible to address the concerns and bring its test to market.”
The federal government issued a statement May 3 to media saying, "In light of the clinical results, Health Canada has placed conditions on the company's authorization to restrict the use of the product to research use only until adequate evidence of clinical performance can be provided.”
These trial-and-error runs are to be expected, said Nielsen.
“You can’t validate on something that hasn’t been approved, so it’s a bit of a cart and horse thing right now,” she said.
And so, there are going to be challenges to rapid point-of-care tests along the way to re-opening and prior to achieving herd immunity. And this reinforces the need for labs to carry out the bulk of the testing.
Devices such as The Cube have “amazing potential,” said Nielsen, but they will take time to be validated for accuracy and then more time to manufacture and distribute. Then, they’ll still need to be administered by public health officials.
“You shouldn’t be able to do a test, get a result and not report it,” said Nielsen.
“It’s in its infancy, it’s an amazing idea, and someone — and I don’t know who that is — someone will have to decide if it can catch 95% of the COVID-19 cases, is that good enough?
“Whereas, the hospital will be catching 99.9%. So, there could be a moment where there’s a false sense of ‘oh I’m fine,’” said Nielsen.
“The nature of point of care testing is it gets better over time. Because we figure out how do we concentrate the antibodies, how do we put a better filter in, how do we tinker with the science,” said Nielsen.
But she warns people should not feel overly confident in advances to rapidly test for COVID-19.
“This device might be for the long haul, this might be for the next five years, or forever — who knows. But I don’t think it will decrease the need for public health labs,” she said.
By comparison, rapid influenza diagnostic testing (RIDT) for the flu has “limited sensitivity to detect influenza viruses in respiratory specimens compared to RT-PCR or viral culture and negative RIDT test results should be interpreted with caution given the potential for false negative results, especially during peak influenza activity in a community,” according to the U.S. Centers for Disease Control (CDC).
Such tests may detect outbreaks but thereafter it is still up to labs to conduct mass testing, notes CDC:
“Public health authorities should be notified promptly of any suspected institutional outbreak and respiratory specimens should be collected from ill persons (whether positive or negative by RIDT) and sent to a public health laboratory for more accurate influenza testing by molecular assays and viral culture.”
Therefore, if mass testing is required to keep people safe by suppressing outbreaks, where does Canada stand in its abilities to do this?
Nielsen said there are significant hurdles — many of them bureaucratic — to overcome if Canada is to become capable of widespread testing for COVID-19.
She’s described the early stages of Canada’s testing strategy as a “completely uncoordinated effort” among provinces.
“Here’s the problem,” said Nielsen of the Canadian Society for Medical Laboratory Science. “It depends on where you are because health is not an integrated service. I’d say what you get in Kamloops is not the same as what you get in Vancouver. And what you get in Ontario is not the same as what you get in B.C.”
Calls for widespread testing, including from powerful American Democrats such as Elizabeth Warren and Joe Biden, depend on the capacity to perform the tests and capacity is dependent on the ability of technologists to accurately process those tests, said Nielsen.
Canada’s chief public health officer Theresa Tam has ambitious nationwide goals for testing.
“We are at the moment working out some of the optimal lab testing strategy going forward,” she told media on April 23. “It is a bit of a target in evolution, but as a first tranche, roughly close to 60,000 is where the provinces can potentially expand to as a target already.”
This may mean shelving other tests, said Nielsen, whose 13,706 members (close to 10,000 of them being technologists) conduct 1.2 million tests daily.
But Nielsen said if the government provides adequate equipment, technologists can juggle both duties (regular tests and COVID-19). But that’s yet to happen, with many labs struggling to procure the PCR devices.
And she says Canada needs to increase the number of licensed testing centres with the appropriate number of lab technologists to supervise lab assistants.
“You can’t replace that knowledge with a layperson; it would be irresponsible to do so. People are saying ‘well we got all these university students we can redeploy; that’s no where you want to go; this is not about people, this is about processes and product, which is equipment and reagents to do the job.”
Washington State-based infectious disease modelling expert Trevor Bedford says, “We will need to massively increase our testing capacity.”
He likened the effort to this generation’s Apollo mission.
“These transmission routes can be reduced by a huge rollout of testing capacity. If someone can be tested early in their illness before they show symptoms, they could effectively self isolate and reduce onward transmission compared to isolation when symptoms develop,” said Bedford on Twitter.
More widespread diagnostic testing, in the absence of accurate serological testing for antibodies, would also give a better understanding of true infection rates.