After testing 476 patients, the Buffalo Veterans Affairs Medical Center has uncovered the possibility of infection from the inadvertent reuse of insulin pens that were intended only for one-time use, but it provided few details.

In November, the Medical Center learned that between October 2010 and November 2012, 716 patients may have been exposed to HIV, hepatitis B or hepatitis C through the possible reuse of insulin pens that were not labeled for individual patients.

The hospital attempted to contact 570 patients by telephone or mail, said Evangeline Conley, a spokeswoman for the hospital. To date, of the 541 living patients, 476 consented to testing for possible infection and nine declined testing. The remaining patients have yet to respond to the hospital, she said.

The Medical Center indicated that initial testing uncovered the possibility of infection, but no details were provided on the nature or extent of the infection in patients.

“We are engaging in an epidemiologic analysis to definitively pinpoint the source of infection and have not yet completed that analysis,” Conley said. “We want to make sure the information we have is accurate and definitive.”

In a similar case, Cattaraugus County Public Health Director Dr. Kevin Watkins earlier this month reported to the Board of Health that at least 12 people tested positive for hepatitis C and one person for hepatitis B after undergoing screening offered by Olean General Hospital because of the possibility that insulin pens were inadvertently reused. Watkins could not be reached to comment further.

Olean General last month mailed 1,915 patients letters recommending they seek testing, after an internal review raised the possibility that some of them may have received an injection from another patient’s insulin pen. It’s still not clear how those people may have been infected, and the meaning of the test results remains uncertain.

The percentage of patients testing positive for hepatitis C at Olean General is less than 2 percent of all those tested, said Dennis McCarthy, a spokesman for the hospital. That rate is lower than the prevalence of hepatitis in the general adult population in the United States, which is about 2 percent.

“We believe that the chance of infection from the use of an insulin pen at Olean General Hospital is almost zero,” said McCarthy.

Hepatitis refers to a group of viral infections of the liver. Hepatitis C virus infection is the most common chronic blood-borne infection in the United States, according to the federal Centers for Disease Control and Prevention.

An estimated 4 million people in the U.S. are infected with hepatitis C. Of those, about 3.2 million have long-term chronic hepatitis C, and the rest have acute infections that get better, according to the American Liver Foundation.

The faulty insulin practices occurred despite a 2009 Food and Drug Administration warning against reusing the devices, as well as a January 2012 alert from the Centers for Disease Control.

Insulin pens were designed for convenient self-injections by diabetics at home. But their use has increased in hospitals as well since their introduction in the 1980s.

The nonprofit Institute for Safe Medication Practices recently issued an alert, recommending that hospitals strongly consider transitioning away from the routine use of insulin pens, even though no cases have been reported yet in which blood-borne pathogens were transmitted from patient to patient.

The Veterans Health Administration National Center for Patient Safety recently prohibited use of multidose pen devices in patient care units at VA facilities, with a few exceptions. In addition, the inspector general at the U.S. Department of Veterans Affairs has initiated a review of practices at the Buffalo VA Medical Center.

The institute noted that the recent cases in Western New York are similar to other incidents elsewhere in the country.

“All it takes is one or two individuals who are not aware that it is unsafe to place a new disposable needle on a pen used for one patient and use it to deliver a dose of insulin to another patient,” the group wrote in its alert. “Completely controlling for this is difficult, perhaps even impossible, given that unsafe pen use has persisted despite educational efforts and monitoring.”