Two-half test is the common name of Hepatitis B Penta test, which detects two antigens of Hepatitis B virus and three antibodies produced by human body against Hepatitis B virus, which are Hepatitis B Surface Antigen, Hepatitis B e Antigen, Hepatitis B Surface Antibody, Hepatitis B e Antibody and Hepatitis B Core Antibody. There are two main ways to check hepatitis B penta in clinic: 1) qualitative examination of hepatitis B penta using enzyme immunoassay; 2) quantitative examination of hepatitis B penta using chemiluminescence method. Hepatitis B 5 quantitative test, with high sensitivity and quantitative manifestation of the results of hepatitis B 5, is often used as an important reference index for antiviral treatment of hepatitis B patients. Hepatitis B 5 qualitative test is relatively less sensitive but inexpensive, and is often used as a screening test for hepatitis B virus infection.