The effect of chemical and heat disinfection of the hemodialysis machines on the spread of hepatitis C virus infection: a prospective study.

Seventeen of our 42 regular hemodialysis (HD) patients (40.5%), and six of our 16 patients on continuous ambulatory peritoneal dialysis (CAPD) (37%) were found to be positive for hepatitis C virus (HCV) antibody in June, 1992. Since the virus was considered susceptible to eradication by the available disinfection methods of the HD machines, the most likely source of transmission was considered to be incomplete application of the universal infection control techniques. These recommendations were strictly applied, but no attempt was made towards designating specific machines for anti-HCV positive patients. Review of data revealed that seven of our 25 previously negative patients (28%) turned positive in the following 12 months. Risk factors such as blood transfusions were excluded in all these patients. A strict protocol of careful chemical disinfection using Citrosteril run at 85 degrees C for 35 minutes after each dialysis session was adopted. Over the following 18 months, six of the remaining 17 negative patients (35.2%) seroconverted. They all had received blood transfusions, 7 to 14 months before (mean 10.5 months). The blood had been screened and had tested negative for anti-HCV antibody. By contrast, none of our CAPD patients who were anti-HCV negative in June 1992, and remained on CAPD, turned positive. The HD machine disinfection techniques were thoroughly reviewed and found to be as prescribed In the absence of other sources of infection with HCV we conclude that the HD machines were the most likely source of transmission of HCV infection and therefore, it is important to assign specific HD machines for anti-HCV positive patients. We have now adopted such a system.