Four evacuees were released from isolation at UC San Diego Health on Sunday, Feb. 9, after the Center for Disease Control (CDC) informed the hospital that they had tested negative for coronavirus. However, after the CDC performed further testing, it was learned that one of them did actually test positive.

According to officials, when the four patients were brought from the hospital to provide samples for testing, three of those four samples were not labeled in compliance with the same regulations between UC San Diego Health and the CDC.

Medical specimens collected from the four patients were mislabeled when they had arrived at the CDC’s lab in Atlanta, according to KGTV.

The samples tested negative while three of those samples had not actually been tested, according to the CDC.

However, as the patients were heading back to the base to finish out their 14-day quarantine orders, further testing revealed that one of the four patients tested positive for the coronavirus.

The infected patient, a woman, had been transported back to the hospital for isolation on Monday morning, Feb. 10.

The woman is reportedly doing well and has minimal symptoms, according to UC San Diego Health.

CDC officials are now investigating whether the infected woman may have come into contact with anyone after they were released for a short time. But based on what they’ve learned so far, they say it appears unlikely anyone else is at risk.