Hepatitis B virus is divided into three antigens: the first antigen is the surface antigen; the second antigen is the core antigen; and the third antigen is the e antigen. After the human body is infected with hepatitis B virus, it will produce three antibodies to the above three antigens, namely hepatitis B virus surface antibody, hepatitis B virus core antibody, and hepatitis B virus e antibody. Therefore, the test for the three antigens and the three antibodies is the hepatitis B triple pair. In recent years, because the detection of core antigen requires cell-breaking technology, which has been very rarely used among clinics, the test is now the hepatitis B two-and-a-half pair.