About two-thirds of the people who might have been exposed to a blood-borne illness at Swedish Medical Center have been tested for hepatitis B, hepatitis C and HIV.
The testing comes after the hospital fired a surgical technician who allegedly tried to swap syringes to steal the powerful painkiller fentanyl.
Rocky Allen, 28, has pleaded not guilty to the two federal charges of tampering with a consumer product and obtaining a controlled substance by deceit or subterfuge.
The medical center and Colorado Department of Public Health and Environment are not releasing the number of patients who tested positive.
Federal prosecutors said Allen used his position at hospitals in four different states to get his hands on the narcotic.
"They'll go to great lengths in order to feed that addiction and unfortunately that does include things like drug diversion and putting other patients at risk, lying, whatever it takes," said Dr. Larry Wolk, executive director and chief medical officer of the Colorado Department of Public Health and Environment.
Wolk is helping investigate Allen and his time at Swedish Medical Center -- where he allegedly tried to swap out a syringe of the drug with another substance.
Federal prosecutors said the now-former surgical technician has a "blood-borne pathogen" but are not saying which one.
Swedish is asking 2,900 patients to be tested for hepatitis B, hepatitis C and HIV.
"You would expect in a population of 3,000 folks that at least six, seven, eight people may come back or are likely to come back positive just as a result of other type of contact not necessarily as a result of exposure to this particular health care employee," Wolk said.
Interpreting the results is complicated.
After an initial test, the state health department takes all the positive results and tries to figure out the origin by interviewing the patients. The people who test positive then get a second test. If that's also positive, the blood samples go to the Centers for Disease Control, where viral sequencing can help answer the question of which positive results stem from exposure at Swedish.
The process could take months.
Two hospitals in Arizona and one in California where Allen briefly worked, are also offering patient testing.
