Hepatitis B virus infection and transfusion medicine: science and the occult

O ccult hepatitis B virus (HBV) “infection” has been characterized as an obscure, covert, concealed, or hidden disease entity that is recognized in a hepatitis B surface antigen (HBsAg)-negative person whose blood and/or liver tissue is found to contain HBV DNA. While there is general consensus for this definition, uncertainty exists as to what other hepatitis B serologic criteria should be included in this description and whether hepatitis C virus (HCV) or human immunodeficiency virus (HIV) should be excluded from the equation. This has created some confusion depending on whether one is dealing with a healthy blood donor or a patient with liver disease. Additional critical issues are whether these individuals are viremic and at risk for progression of their disease or are capable of transmitting HBV to another individual. To place this in perspective, an overview of the current methods used for detecting HBV followed by a summary of the serologic patterns accompanying hepatitis B infection seems to be warranted concluding with a discussion of occult infection based on recently published articles. CURRENT MOLECULAR BIOLOGY OF HBV AND DIAGNOSTIC METHODOLOGY