Repeated Measurements of Hepatitis B Surface Antigen Identify Carriers of Inactive HBV During Long-term Follow-up

In a retrospective, dynamic analysis of almost 300 patients with chronic HBV infection, we found that levels of HBsAg <100 IU/mL identify patients with inactive virus with a high level of specificity. HBsAg levels should therefore be used to define phases of HBV infection in HBe antigen-negative patients.