Getting a COVID-19 test to see family or friends? Good intentions come with risks, experts warn

Seeing elderly grandparents. Heading to a cottage. Gathering with friends and family.

Those are among the reasons why some Canadians are now opting to get tested for COVID-19, even though they're symptom-free, in hopes of gaining a little peace of mind to expand their social network — but it's an approach experts say comes with risks.

Tatiana Kunitskaya, a mother of two in Mississauga, Ont., got tested after the family of one of her youngest daughter's friends requested it. The test was a condition for the girls going to a cottage together.

The hope, she explains, was to make sure the girl didn't bring the illness back home to older loved ones — an issue Kunitskaya wasn't worried about to begin with, since her family has taken precautions for months.

"I just did it mostly for the peace of mind for the person on the other side who requested it," she said.

"You have to be smart about it and respectful, not just for your family, but other families who don't want to be exposed."

Ann Sanderson, a Toronto-based freelance artist and mother to a three-year-old daughter, says getting tested was a recent decision so she could visit her parents in Stratford, Ont. The pair are getting older, she says, and her father has a heart condition.

"I was feeling a little paranoid," Sanderson told CBC News.

Even though Sanderson's family wasn't "taking any chances" beforehand, including staying largely at home and ordering all their groceries online, she felt getting a negative test result would help confirm she wasn't sick.

"I'm not sure if younger people are going to get tested and thinking they're fine forever, or that they'll never get it," she added. "That would be my worry: that people think the test is 100 per cent accurate, and it certainly isn't."

Experts agree that's the major risk with getting tested before social gatherings: the test itself can fairly often give you a negative result, even if you're actually infected with the novel coronavirus.

Tests may give 'false sense of security'

"It may give people a false sense of security," warned infectious disease specialist Dr. Dominik Mertz, an associate professor at McMaster University in Hamilton, Ont..

Testing negative means that, at the point in time you get the test done, there's no virus in your dose that is detectable, he says — with the limitation that it can be a false negative when, for various reasons, there's not enough virus in the sample for a "positive" result.

The timing of the test plays a key role, research shows. A recent study from Johns Hopkins researchers, for instance, found people were far more likely to get a false negative test early on in their infection.

Even the best-case scenario — testing people around three days after the arrival of symptoms — had a false negative rate of 20 per cent, meaning one in five people infected with the virus were deemed negative instead.

"It's not a test that gives you the answer of whether you got infected or not," Mertz said.

"You may be incubating. If you got infected yesterday, and you got tested today, you'll probably get a negative test ... If you see someone in a couple days, you may be infectious."

Results only show 'period in time'

Despite the drawbacks, expanded testing guidelines in many regions over the course of the pandemic mean more people can now get tested for a variety of reasons.

In Ontario, Premier Doug Ford announced the shift back in May, marking the first time the province was promoting testing for people without symptoms.

"If you are worried if you have COVID-19, or that you've been exposed to someone who has COVID-19 — even if you're not showing symptoms — please go get a test," Ford said at the time.

The province has also since implemented new screening policies for long-term care homes, allowing visitors indoors if they can "verbally attest" to having had a negative COVID-19 test result within the previous two weeks.

Mertz says that policy can send mixed messages about the value of testing, which also doesn't prevent you from getting infected any time in the future.

"We have to recognize that a test is imperfect," noted Dr. Eileen de Villa, Toronto's medical officer of health. "It tells you about what your circumstances are at a particular period in time."

Further muddying the waters? Some people never show classic COVID-19 symptoms like a fever or cough even if they do get infected. That means a negative test result could mislead you even further if you're actually carrying the virus without any tell-tale signs.

Residents being 'responsible,' health minister says

Even so, Ontario Health Minister Christine Elliott praised residents taking the extra step of getting tested before seeing loved ones, suggesting they're being "responsible" by doing so.

However, she didn't respond to a CBC News inquiry about whether the province should be providing more information about the potential for false negative results.

Both Elliott and Ford also urged people to continue following public health guidelines alongside any efforts to get tested.

"The golden rule is to make sure you social distance, wear a face covering of some sort, and stay out of large gatherings and large crowds," Ford said on Wednesday.

Mertz stresses while most people heading for tests have good intentions, the results may only provide minimal or misleading information about whether or not someone is actually infected. That means even people who test negative need to protect themselves and others.

"Regardless of what the test result shows," he said, "you should behave in a way that's reasonable."

Both Kunitskaya and Sanderson say getting tested didn't change their behaviour, beyond finally seeing close family and friends.

"I wasn't going to be cavalier about getting tested — then go to a party," Sanderson said.