Interpretation and management of positive anti‐hepatitis B core antibody tests in immunocompromised pediatric patients

Abstract

Intravenous immunoglobulin (IVIg) therapy is increasingly used in the pediatric population, in particular among children with immune‐compromising conditions. Pooled immunoglobulin products are routinely tested for hepatitis B surface antigen (HBsAg) and nucleic acid; however, screening for hepatitis B core antibody (anti‐HBc) is not commonly performed. Thus, the administration of IVIg containing anti‐HBc to children with immune‐compromising conditions may complicate the interpretation of hepatitis B serologic testing in that a positive anti‐HBc test may represent passive transfer of antibody from IVIg or may indicate resolved or chronic hepatitis B infection. Due to the risk of hepatitis B reactivation in immunocompromised patients, a positive anti‐HBc test must be carefully considered. As part of a quality improvement initiative, we identified and reviewed the records of all pediatric patients at our institution who tested positive for anti‐HBc over an 18‐month period. Of 44 total patients with positive anti‐HBc tests, we found that 22 (50%) had previously received IVIg in the preceding 4 months. All but one of these, 21/22 (95%), went on to receive immunosuppressive therapy (IS). Among the patients who received IS, 19 (86%) had not undergone hepatitis B serologic testing prior to IVIg administration and 16 (73%) did not have subsequent testing to distinguish between passive acquisition of anti‐HBc from IVIg and chronic hepatitis B infection. Our single‐center experience reveals that a high proportion of positive anti‐HBc tests in children are presumed to be because of the passive antibody transfer from IVIg. However, a low proportion of patients undergo confirmatory testing, despite the risk of hepatitis B reactivation during IS. We thus propose a risk‐based algorithm for interpretation and monitoring of hepatitis B testing in immunocompromised children.