It is rare for both hepatitis B surface antigen and antibodies to be present at the same time, because there may be two hepatitis B virus subtypes in the serum, one with hepatitis B surface antibodies and the other with hepatitis B surface antigen, and although both are present at the same time, they are not correlated. Another situation may be that the body produces hepatitis B surface antibodies, but the hepatitis B surface antigen in the body has not yet disappeared and seroconversion to hepatitis B surface antigen is about to occur. In another case, surface antibodies may be produced as a result of hepatitis B immunoglobulin vaccination in hepatitis B carriers.