occult hepatitis b (obh) in clinical settings

context occult hepatitis b (ohb), or persistent hbv dna in patients who are hepatitis b surface antigen (hbsag) negative, is a recently recognized entity. in an attempt to summarize the issues, this review presents an overview of the current proposed hypothesis on the clinical relevance and also updates the knowledge on the classification of ohb in different clinical settings. evidence acquisition ohb could be found in different population and clinical backgrounds including: viral co-infections (with either human immunodeficiency or hepatitis c viruses), hbv chronic carriers, dialysis patients, transplantation settings and certain clinical situations (named in here: special clinical settings) with no apparent distinguishable clinical parameters. results the exact magnitude, pathogenesis, and clinical relevance of ohb are unclear. even the possible role exerted by this cryptic infection on liver disease outcome, and hepatocellular carcinoma development remains unknown. conclusions monitoring of individuals with positive anti-hbc, mass immunization programs and improvement in diagnostic tools seem to be important to control the probability of transmission of hbv through cryptic hbv infection.