Hepatitis B surface antibody test is done to identify antibodies that the immune system produces in response to the Hepatitis B virus surface protein. This test is primarily used to screen and diagnose acute and chronic infection or acquired immunity from HBV vaccination. The first response of the body after exposure to Hepatitis B infection is the production of IgM antibodies and then the body then produces IgG antibodies for life. Performed to identify prior exposure to Hepatitis B or whether the vaccination is successful or not. It may also be done to monitor the treatment and the progress of the patient’s recovery. Usually recommended for people when they are in close contact with an infected person or the person has symptoms of Hepatitis B like jaundice, yellowing of the eyes, abdominal pain and dark urine; people who have to get immunosuppressive drugs or chemotherapy, to monitor their response to the treatment, high risk pregnancy, before surgical procedures, response to vaccination, etc.