Standing beside a charcoal grey sedan, Marilyn DeMelo offers a warning to the young woman driving the car.

"It's going to be uncomfortable," she says.

As a front-line nurse, DeMelo is clad nearly head-to-toe in personal protective equipment — plastic gloves, a surgical mask, a face shield, and a long blue covering over her scrubs — and holding a clear container housing a long nasal swab.

She instructs the woman to keep her mouth closed, and cover it with a tissue.

"Ready?" she asks, before sliding the swab up her patient's nose so it can collect any possible traces of the new coronavirus.

The whole thing takes roughly five seconds. And after a small groan of discomfort, the woman drives away, leaving DeMelo rushing to pack up the sample on a small table nearby so it can be safely sent away for lab testing.

Then it's on to the next one. And the next one. And the next one.

It's close to 5 p.m. on a weekday afternoon as snow is starting to fall around the big white tent where DeMelo and a handful of other health-care workers are operating this drive-thru COVID-19 testing centre near Etobicoke General Hospital.

On this day in April, they've spent hours working in winter-like conditions, with the temperature hovering around the freezing mark as wind keeps whipping through the tent while drivers stay warm in their cars.

Their efforts come as the province has been pushing to boost testing numbers, with these outdoor facilities offering an unprecedented way to test dozens of people without them ever setting foot in a hospital.

"We're seeing everybody from young children to the elderly coming through," says Donna-Lyn Moore, interim manager of the Etobicoke General Hospital COVID-19 assessment centre.

Nurses with the William Osler Health System braved the cold on Tuesday to perform COVID-19 testing at a drive-in centre near Etobicoke General Hospital. (Evan Mitsui/CBC)

More than 100 patients each day

Moore, who's bundled up in a long grey parka, says the number of people driving through this makeshift facility in a north Etobicoke parking lot has gone up from 40 each day to more than 100 since it first opened at the end of March.

That's a good thing, Moore says, because those patients aren't clogging up hospitals.

At the same time, she notes the people driving in are getting sicker — likely because they're now later on in their illness — and on this day, the team even sent some to the main hospital's nearby emergency department.

Nurse Marilyn DeMelo was among those wearing full protective gear at the site, including a face shield over her surgical mask. (Evan Mitsui/CBC)

There are roughly a dozen similar drive-thru sites across Ontario, and provincial officials say more than 5,500 swabs have been taken in total between March 18 and April 14, marking the clearest period of available data.

That's around 10 per cent of the total swabs taken by all assessment centres during that time frame, according to the Ministry of Health.

Despite the benefits of the efficient approach, which feels more like grabbing a coffee than being tested for a potentially-deadly disease, it can be a uniquely challenging atmosphere for the health-care workers.

This Etobicoke drive-thru testing site has gotten busier since it opened at the end of March. On this day, there's an hour-long lineup. (Evan Mitsui/CBC)

Lineups can take more than an hour

On this late afternoon at the Etobicoke site, cars are circled around half the parking lot.

People first pass by security guards, then to a screening tent where they're either given the green light to get tested or sent home. Patients without symptoms are among those told to keep driving, while people with severe issues like major shortness of breath are encouraged to go to a hospital.

The lineup can take 15 minutes on a light day, or more than an hour on a busy day like this.

Donna-Lyn Moore, interim manager at Etobicoke General Hospital's COVID-19 assessment centre, says having more people going through this drive-thru site means fewer people clogging up hospitals. (Evan Mitsui/CBC)

Inside the final testing tent, nurse Teresa Thomas Cross holds her plastic-gloved hands up to one of the heat lamps encircling the enclosure.

She's been here since around 9:30 a.m., helping test the steady stream of people, packaging up the samples, and ensuring the wind doesn't blow the crucial paperwork off their workspace by securing it all with laundry clips.

At one point, as another strong gust threatens to undo all their meticulous work, Cross and DeMelo hoist up the table to move it farther into the tent — adding extra steps back and forth to each car, which all starts adding up as the hours tick by.

"It's challenging," Cross admits. "Your fingers are cold, so it's hard to do the delicate work."

Nurses Teresa Thomas Cross and Marilyn DeMelo, with the William Osler Health System, package up samples while the wind whips through the testing site. (Evan Mitsui/CBC)

Accessible, approachable

But Dr. Mahin Baqi, an infectious disease specialist at the hospital, says it's also crucial.

These screening centres are more accessible and approachable than an emergency department, which could mean more virus carriers with milder symptoms are willing to get tested.

"It's important to do all the screening because that will allow us to follow the people that are positive and do the proper contact tracing," Baqi says, referring to the process of identifying all the people who might have come into contact with someone who's infected.

Frontline health-care workers use a fresh pair of gloves for each person who drives through. After a few hours, those gloves start piling up. (Evan Mitsui/CBC)

Getting a better handle on those contacts means more follow-up and isolation of potential carriers, which she says will help fight the already months-long outbreak.

With that in mind, the team inside the tent is intent on staying the course — braving all the wind, snow, and hours-long lineups of cars.

"We're just doing what we can to get through this COVID-19 crisis," Cross says.

Carefully packing up the testing samples in the final step in the process at this Etobicoke drive-thru site. (Evan Mitsui/CBC)

Ontario drive-thru COVID-19 test centre locations