The nurse spoke to CNN, but did not want to reveal her name or where she worked for fear she would be fired.
The nurse said she went undetected because staff was not being tested.
"Two weeks ago, I was feeling back pain, a lot of back pain, and then one night, had really bad chest pain," she described, claiming she was told hospital staff would not be tested when she asked.
She continued to work and said she wore the same mask and uniform all day, from patient to patient.
"Yes. Yes we do. I'm touching that mask. It's on my face. I'm putting it back on, virus flies in the air, it goes right up in my nose. It's so easy to get contaminated when you have to put on something that already has virus on it," she said.
According to the nurse, since the emergency room refused to test staff, she went there in the middle of the night when she knew a friend would be on duty.
"I said, 'Please. Just this one time. I want to make sure I don't have it. I don't want to spread anything,' and so she tested me," she explained.
The results came back five days later. She tested positive.
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The nurse told CNN she's worried she may have infected staff members, visitors and patients.
"That story is heart-wrenching. And as a clinician or just a human being, it's horrible," said Dr. Peter Pronovost, author of "Safe Patients, Smart Hospitals" and the Chief Clinical Transformation Officer at University Hospitals.
Pronovost says he wishes the U.S. could do what's being done in some other countries.
At Haddasah Medical Center in Israel, staffers utilize tests that aren't needed for patients and test all health care workers every five days.
"We feel that this is extremely important in order to protect our entire workforce and our patients," the hospital said.
As for the nurse in New York, she is now home in isolation and said she's feeling better. She also believes there are doctors and nurses at the hospitals where she works now who are positive for coronavirus.
In addition to testing kits, personal protective equipment and ventilators are also in short supply.
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