A resident of Brooklyn, New York, went to the emergency room with a fever and cough on Thursday. He'd just returned from Japan, where more than 200 people have the new coronavirus.

His case was not "of concern" based on the official criteria from the Centers for Disease Control and Prevention, however, so he did not receive a coronavirus test. CDC guidelines allow him to resume his normal life, including taking the subway.

The man still doesn't know whether he has the coronavirus, so he's quarantining himself in his apartment just in case.

The case points to the CDC's limited capacity for testing, which could leave cases undetected.

For the latest case total, death toll, and travel information, see Business Insider's live updates here.

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When a 35-year-old man went to a New York City hospital with a fever, a cough, and aches, emergency-room staffers put him in isolation and suited up in gowns, gloves, and goggles. He'd recently returned from a business trip to Japan, where at least 230 people have tested positive for the new coronavirus.

Doctors at the NYU Langone Health—Cobble Hill emergency department in Brooklyn suspected he might have COVID-19, the illness caused by the new virus. Tests for 20 other viruses came back negative, including five strains of flu. But the Centers for Disease Control and Prevention denied the hospital's request to test for the novel coronavirus, the man told Business Insider, because his condition wasn't severe enough to hospitalize him.

Officials even told the hospital that the patient could resume life as normal, including taking the subway to his workplace in midtown Manhattan, he said.

"They kind of left me in this state which was kind of a choose-your-own-adventure," the man said. Business Insider confirmed his identity and reviewed paperwork from his hospital visit but is keeping the man anonymous for security reasons.

"If this turns into a pandemic or whatever this is, it shouldn't come down to individual decisions," he added.

The man said his doctor did not agree with the CDC's verdict and recommended ways the patient could quarantine himself at home. He's taking the advice, though he still doesn't know for sure whether he has COVID-19.

The case highlights a major hurdle for containing the new coronavirus in the US: Testing capacities are still limited.

"Other countries are testing much more broadly than we are," William Schaffner, an infectious-disease specialist at the Vanderbilt University School of Medicine, previously told Business Insider. "We are trotting along while they're racing along."

In a press briefing Tuesday morning, addressing New York's second confirmed COVID-19 case, Gov. Andrew Cuomo pointed to the same problem.

"We're at a couple of hundred tests per day, so you prioritize who can be tested," Cuomo said. "You don't have the capacity to test everybody 'just in case.'"

Limited testing capacities mean cases can go undiagnosed

In the hospital, the man said, health workers scanned his chest to check for pneumonia and ordered testing for 20 basic viruses. He tested negative for all of them. The man's chest scan came back clear, and his symptoms weren't severe enough to keep him in the hospital.

His doctor told him she had requested a COVID-19 test from the state's health department but was told he didn't need one.

"She said, basically, if we didn't hospitalize you … then you don't meet the criteria that's set by the CDC, which means we can't perform testing through the CDC," he said.

According to CDC guidelines, those who have recently traveled to Japan are considered likely to have COVID-19 only if they have symptoms severe enough for hospitalization. The same standards apply to people who have traveled to China, Iran, Italy, and South Korea.

A signed letter from the man's ER doctor, reviewed by Business Insider, said the Department of Health had advised the man that his case was not "of concern to have COVID-19." The doctor did, however, recommend "that he stay home until fever resolves."

The New York State Department of Health declined to comment for this story, and the CDC did not respond to a request for comment in time for publication.

Coronavirus test kits in Krasnodar, Russia, on February 4. AP Photo

The CDC had tested only about 470 people in the US for COVID-19 as of Sunday, according to the agency's official count. The CDC has since removed those testing numbers from its website. Alex Azar, the US secretary of health and human services, told ABC on Sunday that 3,600 Americans had been tested.

"We're still dealing with a test that is limited in its availability, so we still have to prioritize by risk," Bela Matyas, the health officer in California's Solano County, said at a Thursday press conference.

Matyas said that was one of the reasons a California patient spent multiple days in two hospitals without getting tested. At least two healthcare workers who treated that patient have since been diagnosed.

Ten people in New York City have been tested for COVID-19, and another 31 have been tested elsewhere in New York as of Tuesday. The New York State Department of Health confirmed its first case on Sunday — a woman in her late 30s who had recently traveled to Iran — and announced its second case on Tuesday.

Passengers on the subway in the Queens borough of New York City on February 2. (None of the individuals in this photo is the patient described in this story.) Nick Zieminski/Reuters

"In New York state, the [first] person who tested positive was only the 32nd test we've done in this state — that is a national scandal," Matthew McCarthy, a Manhattan physician and assistant professor of medicine at Cornell, told CNBC on Monday.

South Korea, by contrast, has implemented free coronavirus-testing drive-thrus and tested more than 109,000 people.

What's more, many CDC tests distributed to state labs have been faulty, causing more than half the labs to receive inconclusive results.

"It is easy to do for some countries, but what happened in the US is the CDC created a test, sent it out to all 50 states and then said, 'Wait, hold up, don't use it,'" McCarthy said.

He added: "I still have to call the Department of Health. I still have to make my case, plead to test people."

Uber trips and a vague 'viral illness' diagnosis

A man outside a military hospital in Santo Domingo, Dominican Republic, on Sunday. Ricardo Rojas/Reuters

While in Japan, the man said, he wore a mask most of the time but couldn't avoid crowded train stations. Halfway through the trip, he developed a mild cough. He returned to New York on Tuesday, February 25, landing at Newark Liberty International Airport.

Over the next couple of days, he started to feel achy and feverish, describing a feeling of "pure burning, like my whole body burning."

He called NYU Langone on Thursday.

"I felt like things were just compounding," he said. "It felt like symptoms were adding up and things were on an upward trajectory. So that made me nervous."

A hospital staffer told him to come into the emergency department, the man said, so he called an Uber. When he arrived, a nurse gave him a surgical mask and escorted him to a private room.

"The next time someone came into that room, they were in a quarantine outfit essentially," he said. "Full face covers, full apron, shoes wrapped up, and gloves, plastic glasses. Literally no part of their body exposed."

A medical professional at a preliminary testing facility at the National Medical Center in Seoul, South Korea, on February 21. Chung Sung-Jun/Getty Images

But after his examination, the man was cleared to leave the hospital with a vague diagnosis of "viral illness."

He called another Uber to take him home.

'The ultimate test of my own personal morality'

The patient said the ordeal had proved expensive. He went to the ER because he feared he'd been exposed to the new coronavirus, he said — normally, he wouldn't spend money on an emergency-room visit for a fever and a cough.

What's more, the man shares a one-bedroom apartment with his girlfriend, so he said she's staying in a hotel to avoid contact with him. She has dropped groceries off in his building's lobby, he added, and also left him the medications that doctors prescribed: the steroid Prednisone, which suppresses inflammation, and benzonatate to treat his cough.

"It's like the ultimate test of my own personal morality," he said between audible bouts of coughing. "Are you willing to spend thousands of dollars going to the ER, paying for hotels, and isolating yourself so you don't get people you don't know sick?"

Newark Liberty International Airport. Getty Images

The man added that while he knew the recommended quarantine period was 14 days, he was not sure whether that time period should start when his cough began, when his fever began, or when he visited the hospital. He said he'd been trying to work from home and was sleeping a lot, watching TV, playing video games, and checking his temperature several times a day.

He is starting to feel better: He said his fever, which reached 102 degrees Fahrenheit on February 25, was gone, though his cough had not improved.

He's worried he may have passed the virus to his girlfriend.

'I can't imagine I'm the only one'

The man said he'd been repeatedly calling the New York State Department of Health to ask whether it had changed the criteria or decided to test him, but he has heard nothing.

He said he understood that the CDC was prioritizing tests for people who develop severe symptoms. But he worried that coronavirus patients could be slipping through the cracks.

"I can't imagine I'm the only one coming back from one of those countries with minor flu-like symptoms," the man said, adding that he thought New York health officials should have tested far more people by Saturday.

"It doesn't make any sense to me that we've only tested eight people," he said. "It doesn't make any sense. It's not possible unless there's other people like me who tried to get testing and have been denied testing and just haven't spoken up about it."

Aria Bendix contributed reporting.