The first of the five hepatitis B tests is called the hepatitis B surface antigen. A positive surface antigen indicates that you are currently infected with the hepatitis B virus and are a person infected with the hepatitis B virus. The surface antigen of hepatitis B is in the circulation, mainly because the hepatitis B virus replicates in the body, and the most common component of the replicating hepatitis B virus particles is the surface antigen, as it is present on the surface of the virus’ coat. And if the hepatitis B surface antigen is positive, this will often not be positive alone, but will be accompanied by a positive hepatitis B core antibody, and sometimes by a positive hepatitis B E antigen or E antibody. Once the hepatitis B virus infection is confirmed, the DNA quantification of the hepatitis B virus should be checked to determine the amount of virus replication, as well as liver function and liver ultrasound to determine if the hepatitis B virus has caused damage to the liver and other organs.