Hepatitis B surface antibody is greater than the reference value, indicating that the hepatitis B surface antibody is positive, i.e., the body has immunity to the hepatitis B virus. This antibody is a protective antibody, which is beneficial to the body, and comes from the hepatitis B vaccination or is produced by the body itself after exposure to the hepatitis B virus. However, this antibody is not constant and the antibody titer decreases over time, and the antibody can exist for about 5-10 years. Therefore, the antibody titer needs to be monitored regularly, and the antibody titer can be re-injected with the hepatitis B vaccine if it disappears.