A hepatitis B surface antibody titer of 1000 IU/L or higher indicates a strong immunity to the hepatitis B virus, which generally lasts for 5-10 years. The five hepatitis B tests include surface antigen, surface antibody, e antigen, e antibody and core antibody, of which hepatitis B surface antibody is the only protective antibody. The higher the titer of antibody, the stronger the immunity to hepatitis B virus. If the hepatitis B surface antibody exceeds 1000 IU/L, it indicates that the subject has a very light resistance to the hepatitis B virus and is not susceptible to hepatitis B. The immunity of such patients can last up to 5-10 years. With the extension of time, the titer of surface antibody will gradually decrease and the patient’s immunity to hepatitis B will gradually decline. Therefore, it is recommended that the subject should have a hepatitis B two-to-one test every 2-3 years, and if the titer of hepatitis B surface antibody is too low, he needs to be vaccinated again with hepatitis B vaccine to enhance immunity against hepatitis B.