Hepatitis B virus core and core-related antigen quantitation in Chinese patients with chronic genotype B and C hepatitis B virus infection.

BACKGROUND AND AIMS: Hepatitis B virus (HBV) core-related antigen (HBcrAg) and HBV core antigen (HBcAg) assays were developed for the measurement of serum HBV load. The aim of this study was to assess the clinical utility of these assays in Chinese patients with chronic genotype B and C HBV infection. METHODS: One hundred and ninety-three chronic hepatitis B patients were enrolled. Serum HBcrAg and HBcAg were measured by chemiluminescence enzyme immunoassay, and HBV-DNA was measured by using a sensitive polymerase chain reaction assay. The data were analyzed in patients with HBV genotype B (HBV/B) and genotype C (HBV/C). The HBcrAg/HBcAg ratio was calculated and compared between patients with and without hepatitis B e antigen (HBeAg). RESULTS: The concentrations of HBcrAg and HBcAg showed significant positive correlation with the HBV-DNA concentration in both HBV/B (r = 0.79, P < 0.001, and r = 0.77, P < 0.001, respectively) and HBV/C (r = 0.87, P < 0.001, and r = 0.90, P < 0.001, respectively). The cut-off for a positive HBcAg corresponded to approximately 4.5 log copies/mL, and that for a positive HBcrAg result corresponded to 3-4 log copies/mL. The HBcrAg/HBcAg ratio was higher in patients with HBeAg than in those without HBeAg. CONCLUSIONS: The HBcrAg assay and HBcAg assay are clinically useful in viral quantitation of HBV/B and HBV/C. A combination of these assays would be a valuable tool for analyzing the clinical status of HBV infection.