HBsAg quantification for identification of liver disease in chronic hepatitis B virus carriers

BACKGROUND & AIMS: Quantification of hepatitis B surface antigen (HBsAg) has been proposed as a useful diagnostic marker for clinical staging (identification of inactive carrier state) and prognosis of chronic hepatitis B virus (HBV) infection. The aim of this study was to investigate the correlation between HBsAg levels in serum and histological liver damage in patients with chronic infection. METHODS: HBsAg levels in serum (by Abbott Architect) were related to HBV DNA, ALT and histological score (n=160) and covalently closed circular DNA (cccDNA) (n=84). RESULTS: HBsAg levels correlated with cccDNA, serum HBV DNA, ALT and high inflammation scores (P<0.001). Among HBeAg-negative patients, an HBsAg level below 3.0 log10 IU/ml identified minimal liver damage (normal ALT and mild inflammation) with a predictive value of 92% (alone) or 96% (in combination with HBV DNA<4.0 log10 copies/ml), whereas an HBsAg level above 3.5 log10 IU/ml identified severe inflammation with a predictive value of 16% (alone) or 33% (in combination with HBV DNA>5.0 log10 copies/ml). CONCLUSIONS: HBsAg levels reflect clinical stage and liver disease, and a combined quantification of HBsAg and HBV DNA may improve clinical staging.