Bryan Bordeaux rolls up to the third floor of the garage near Fenway Park in a black BMW with his 4-year-old son in the back seat. He feels as though he has the flu, with a cough and some shortness of breath, he says. And as a primary care doctor himself, he figures he probably has COVID-19, and he probably contracted it on a recent trip to Disney World.

"We’re on quarantine," Bordeaux says. "As soon as I started having symptoms Saturday night, we decided to put our family on quarantine — my wife, my son and I."

But tests to confirm his self-diagnosis have been hard to get — the criteria for who can get them have been very strict and the supplies very limited.

"I actually was trying to get drive-through testing yesterday," Bordeaux says, "but this wasn’t up and running here, there was nothing in the city that I was aware of."

That’s changing as health care venues scramble to set up ways to test patients without bringing them inside where they can infect others. The testing sites include tents outside hospitals, and at least half a dozen states have opened drive through clinics.

On Monday, Atrius Health — a giant medical network with more than 700,000 Massachusetts patients -- set up three drive-through testing centers, including this one in the garage near Fenway Park. The other two are in Braintree and Peabody, and Atrius aims to have three more up and running by the end of the week.

They’re not wide open to all comers.

"There definitely is a ton of demand out there," says Lori Stevens, the nursing director for urgent care at Atrius. The drive-through testing is only for Atrius patients who have already phoned, been evaluated and given an appointment, she says.

Atrius Health medical staffers at the Harvard Vanguard garage in the Fenway area administer a drive-through coronavirus test on the operation's first day. Atrius plans five other drive-through testing sites by the end of the week. (Carey Goldberg/WBUR)

It’s a specific group of patients: "People who we feel don’t need an examination, so they just need the test.

Medical assistant Yadira Sarmiento — garbed in full protective gear including gloves, gown and face shield — says the test is simple: a swab up the nose. The drive-through tests for the flu as well.

"So we first go and do the flu swab," she says, "and then we do the COVID — that also goes in your nose. We stick the COVID swab in for like a few seconds, and then that’s it!"

The tests go to the commercial lab company Quest, and results come back in two to five days. The Fenway garage operation aims to handle at least 40 tests a day soon.

Stevens, the urgent care nursing director, says the biggest challenge in setting up the drive-through clinic has been doing it in addition to everything else in these coronavirus times.

"So we see patients in the clinic, and we’re doing telephonic — we had to get that up and running," she says. "And then being able to try to get enough staff to be able to staff this as well as everything else that we’re doing."

The coronavirus tests are free to patients, with no co-pays, and Stevens says at this point, the plan is to continue the drive-through testing indefinitely.

Other medical groups have opened drive-through clinics on Cape Cod and in Middleton, Mass., the Boston Globe reports.

Bryan Bordeaux, the doctor getting tested in his car, says his wife is having some symptoms too and will likely come in soon for a drive-through test. And he may need to be tested again.

"If I test positive, then I need to be tested and make sure I’m cleared to go back [to work] so I don’t spread this to my patients," he says. "So there’s a big public health implication here in making sure that I know that I’m clean."

Epidemiologists estimate that thousands upon thousands of Massachusetts residents need to be tested. Though most won't develop severe symptoms, the testing allows doctors to diagnose patients and public health authorities to get a better handle on the spread of the virus.