(CNN) Errors by a hospital in San Diego and the US Centers for Disease Control and Prevention led to a woman with the novel coronavirus being sent back to Marine Corps Air Station Miramar instead of isolation at the hospital, according to a health official familiar with the situation.

The woman was among Americans in federal quarantine at the base, and is the first US evacuee from China known to be infected with the novel coronavirus

She flew to the base on February 5 on a US Department of State flight evacuating Americans from Wuhan, China. The next day, she started experiencing symptoms of the novel coronavirus and was taken to UC San Diego Health. Three other people exhibiting symptoms were also transported to the hospital.

The hospital sent their specimens to a CDC lab in Atlanta for testing. According to the source, three of the four specimens were incorrectly labeled upon arrival and so they were not tested. The CDC lab did not realize the specimens were from the Miramar patients.

When no results were reported back, CDC staffers mistakenly gave UC San Diego Health the results of other patients who tested negative. That mistake led to the Miramar patients being transferred back to the base Sunday afternoon.

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