Hepatitis B is characterized by the serological markers of the hepatitis B virus, which we call the two-and-a-half pairs, including surface antigen, surface antibody, hepatitis B E antigen and hepatitis B E antibody, core antibody and core antibody IgM. These laboratory tests can clarify whether the hepatitis B virus is infected and the stage of infection of the hepatitis B virus. Positive surface antigen indicates hepatitis B virus infection, while positive surface antibodies are protective antibodies that indicate immunity to the hepatitis B virus and are seen in patients recovering from hepatitis B and those who have received the hepatitis B vaccine. A positive hepatitis B E antigen indicates hepatitis B virus infection and active hepatitis B virus replication, while a positive hepatitis B E antibody indicates hepatitis B virus infection, but in a quiescent phase or with low replication. Positive hepatitis B core antibody, however, does not distinguish between previous infection, or current infection, regardless of whether the virus is cleared, as long as the infection is hepatitis B virus, the core antibody is a positive result, core antibody IgM suggests acute hepatitis B or an acute attack of slow hepatitis B.