Hepatitis B antibody mainly refers to hepatitis B surface antibody. Hepatitis B surface antibody greater than 2.4U/L indicates that the human body has been infected with hepatitis B virus, because only after the human body has been infected with the virus, the immune system will secrete the corresponding antibody, however, hepatitis B surface antibody greater than 2.4U/L indicates that hepatitis B surface antibody is negative, and at this time the immunity to hepatitis B is low, so it is also necessary to inject the relevant vaccine. Under normal circumstances, if the human body has not been infected with hepatitis B virus and has not been injected with hepatitis B vaccine, the body’s hepatitis B surface antibody is 0U/L, but if once infected with hepatitis B virus, the body’s antibody number will rise, but with the treatment and recovery of the disease, the number of antibodies will also decline, and at this time there will be a phenomenon of hepatitis B surface antibody is greater than 2.4U/L. If a normal person receives hepatitis B vaccination, the surface antibody in his body will be more than 10U/L, so this kind of people is still in the high-risk group, although the disease has been controlled, but the immunity of the body to hepatitis B is relatively low, so there is a chance of recurrence of the disease. If you find that the surface antibody of hepatitis B is low after hepatitis B examination, you should get hepatitis B vaccine in time to improve your immunity and avoid infection.