Occult hepatitis B virus infection in chronic hemodialysis patients in Korea

Background/Aims: Occult HBV infection that is serum HBsAg negative but HBV DNA positive is thought to be a contributing factor to ongoing HBV transmission within hemodialysis units. In the present study, the prevalence of occult HBV infection was investigated in patients on chronic hemodialysis in Korea, an endemic region for HBV. Methodology: Eighty-three patients undergoing maintenance hemodialysis at Samsung Medical Center, Seoul, South Korea were included. Serum samples were obtained from all patients. Testing for HBsAg, anti-HBs and anti-HBbc was performed by an electrochemiluminescence immunoassay. HBV DNA was detected by the nested PCR method. Results: Among the 83 patients, 4 (4.8%) were HBsAg positive and HBV DNA positive. The remaining 79 patients were confirmed HBsAg-negative/HBV DNA-negative. Thus, the prevalence of occult HBV infection was 0%. All of the HBsAg-positive patients were anti-HBs-negative/anti-HBc-positive. Of 79 HBsAg-negative patients, 58 (73.4%) were anti-HBs positive and 52 (65.8%) were anti-HBc positive. Conclusions: The present study showed that the prevalence of occult HBV infection in chronic hemodialysis patients at our center in Korea was not increased compared to the rates of low endemic regions. Furthermore, occult HBV infection was not a contributing factor in HBV transmission in the hemodialysis unit studied.