Occult hepatitis is defined as having clinical manifestations of chronic hepatitis, such as weakness, loss of appetite, abdominal distension and other symptoms, and elevated transaminases on liver function tests. However, the five hepatitis B tests are negative for hepatitis B surface antigen and positive for hepatitis B virus DNA and hepatitis B virus DNA in liver tissue. In addition to positive hepatitis B virus DNA, patients may have positive hepatitis B surface antibody, positive hepatitis B E antibody, and positive hepatitis B core antibody. About 20% of patients with occult chronic hepatitis B are negative for all five markers of hepatitis B. Diagnosis is made mainly by the detection of hepatitis B virus DNA, especially if hepatitis B core antibody is consistently positive. If transaminases in liver function tests are consistently or repeatedly abnormal, hepatitis B virus DNA testing should be done, and if necessary, liver puncture for hepatitis B virus DNA in liver tissue should be done to clarify the diagnosis.