Clinical Usefulness of HBsAg Quantification in Patients with Chronic Hepatitis B Infection

Context Quantitative hepatitis B surface antigen (qHBsAg) levels have been shown to assist the management of patients with chronic hepatitis B virus (HBV) infection and reflect the level of transcriptional activity of covalently closed circular DNA (cccDNA). It has been indicated the importance of co-operative use of qHBsAg and HBV-DNA for diagnosis and monitoring of CHB treatment. Evidence Acquisition In order to achieve a comprehensive approach in HBsAg quantification, an extensive search was done using relevant keywords in major medical libraries to collect, categorize, and summarize data in different sections. Results A combination of qHBsAg < 1000 IU/mL and HBV-DNA < 2000 IU/mL can identify inactive carriers. qHBsAg levels are changed during the natural history of HBV infection that progressively declines from the immune tolerance to the inactive phase. Conclusions The use of qHBsAg in chronic hepatitis B (CHB) patients may bring about important complementary information regarding HBV DNA during treatment and help predict the treatment outcome.