Qualitative positive hepatitis B virus surface antibodies indicate that the body produces hepatitis B surface antibodies, which are produced either by infection with the hepatitis B virus and a strong immunity of the own body, or by vaccination against hepatitis B. This antibody is a protective antibody that can effectively prevent infection with the hepatitis B virus. The test is divided into two types: qualitative and quantitative. A positive qualitative test only indicates the production of surface antibodies, but it does not determine how much antibody titre is present. The quantitative test can clarify both whether the test is positive and how high the antibody titer is. Generally, the higher the titer of the antibody, the stronger the protective effect. The level of the antibody is not constant and will gradually decrease over time. Therefore, it is important to monitor the level of hepatitis B surface antibody regularly, preferably with a quantitative test. If the hepatitis B surface antibody is qualitatively negative, or if the quantitative level of hepatitis B surface antibody is <10 IU/mL, the antibody can be obtained by re-injection of the hepatitis B vaccine.