Santa Rita Jail in Dublin, Calif. (KTVU FOX 2)

A nurse in Santa Rita Jail has tested positive for the novel coronavirus, the first positive test in the jail, according to jail officials.

However, the test was conducted by a private laboratory that has not yet been approved for the Centers for Disease Control and Prevention, so to confirm the case requires further testing.

The jail will conduct a contact investigation for all the people who came into contact with the nurse before diagnosis. The nurse, who worked for Wellpath Health Services, had worn an N95 mask at work, so risk of transmission was low, according to jail officials.

The positive case follows at least one confirmed exposure and several possible exposures at the jail.

One housing unit was placed in quarantine this week after a deputy became ill and was tested, according to jail officials. As of Wednesday, the deputy's test results were outstanding.

Over the weekend, a homeless woman was arrested in Pleasanton for public intoxication and booked into jail. She was taken to a hospital and tested after she developed a fever.

Alameda County sheriff's spokesman Sgt. Ray Kelly said that he expects her test results to be returned sometime on Thursday.

Last week, an Oakland Police Department detective interviewed a suspect in custody. The detective later tested positive for COVID-19 and is one of three officers who have tested positive for the disease thus far.