The CDC reported Thursday that organs and tissue taken from the body of a middle-aged Kentucky man turned out to have been infected with hepatitis C virus and cited four instances in which transplant recipients became infected with that virus.

The donor died in March 2011 two days after suffering traumatic brain injury from an all-terrain-vehicle accident. At the time, his father reported that his son had not been a user of intravenous drugs, but it later became clear that the two had not been in close contact during the year before the man’s death, so the father may not have been aware of his son’s recent behaviors or health condition. The man had a history of substance use and had been incarcerated for five months 10 years before his death; he received blood transfusions shortly before he died.

The organs and tissue taken from his body were tested before transplantation, but those tests were initially deemed negative. Only after two recipients became infected, six months after their transplants, was it discovered that one of the tests had wrongly been recorded as negative when in fact the tissue had tested positive for hepatitis C virus.

Recipients of infected organs included a 41-year-old-man receiving a kidney, a 46-year-old woman, also receiving a kidney, and a 51-year-old man, who received a liver. The liver recipient had a history of hepatitis C before receiving the organ. A fourth patient had received a cardiopulmonary patch; this is the first known instance in which hepatitis C virus was transmitted via a cardiopulmonary patch, the CDC says.

Before being transplanted, organs are subjected only to a test to detect antibodies in the blood, indicating an infection. Tissue is subjected to both a blood test and a nucleic acid test; it was that report that was misread. A tissue sample from the donor was retested and the positive finding confirmed.

The CDC report notes that the case highlights opportunities to improve the system, by perhaps required nucleic acid testing for organs, reducing the risk of error in reading lab test results, and promoting more efficient communication among involved parties when an infection is discovered.