The prevalence of "anti-HBc alone" and HBV DNA detection among anti-HBc alone in Korea.

The "anti-HBc alone" is a frequent serological finding in clinical laboratories, making it difficult to determine whether the HBV infection has resolved. The objectives of this study were to investigate the prevalence of anti-HBc alone and HBV DNA detection (occult HBV infection) among anti-HBc alone, and to describe the demographic and clinical characteristics of anti-HBc alone. A total of 17,677 sera referred from the Health Promotion Center (HPC group, 4,014 sera) as well as all the hospital clinical departments (Patient group, 13,663 sera) were tested for HBs Ag, anti-HBc, and anti-HBs. HBV DNA test using real-time PCR was performed on 230 anti-HBc alone. The prevalence of anti-HBc alone was 8.9%, significantly higher in the Patient group than in the HPC group. The prevalence of anti-HBc was higher in men than women and was increased with age. Very low levels of HBV DNA were found in only 4 (1.7%) out of 230 subjects with anti-HBc alone. They were patients with conditions unrelated to chronic liver disease. Considering the high prevalence of anti-HBc alone, the frequency of occult HBV infection among anti-HBc alone was unexpectedly low. In addition, HBV viral load was low in these patients. Further studies are required to determine the clinical significance and infectivity of anti-HBc alone, in conjunction with very low levels of HBV DNA and to standardize the detection methodology for both anti-HBc alone and HBV DNA.