Hepatitis B surface antigen serum levels help to distinguish active from inactive hepatitis B virus genotype D carriers.

Background & Aims The accurate identification of inactive (serum HBV-DNA persistently ≤2000 IU/mL) hepatitis B virus (HBV) carriers (IC) is difficult because of wide and frequent HBV-DNA fluctuations. We studied whether hepatitis B surface antigen (HBsAg) serum levels (HBsAgsl) quantification may contribute to diagnosis of HBV phases in untreated hepatitis B e antigen-negative genotype D asymptomatic carriers. Methods HBsAgsl were measured at baseline and end of follow-up and correlated with virologic and biochemical profiles of 209 consecutive carriers followed-up prospectively (median, 29; range, 12–110 months). HBV phases were defined after 1-year monthly monitoring of HBV-DNA and transaminases. Results HBsAgsl were significantly lower in 56 inactive carriers (IC) than 153 active carriers (AC): median, 62.12 (range, 0.1–4068) vs median, 3029 (range, 0.5–82,480) IU/mL; P P = .002. HBV infection was less productive in IC and AC1 than AC2 (log 10 HBV-DNA/HBsAgsl ratios 0.25 and 0.49 vs 2.06, respectively, P P = .023). The combined single point quantification of HBsAg ( 10 IU/mL, respectively, P Conclusions HBsAgsl vary during chronic hepatitis B e antigen-negative genotype D infection and are significantly lower in IC. Single-point combined HBsAg and HBV-DNA quantification provides the most accurate identification of IC, comparable with that of long-term tight monitoring.