For a normal person who has not had the hepatitis B vaccine, the surface antibody to hepatitis B should be less than 10mIU/mL, which means it is in the negative range. This is because there is no exposure to anything that can raise the surface antibody, while for people who have been vaccinated against hepatitis B, the whole vaccine should still make the antibody rise higher, and this value should preferably be above 100mIU/mL, but it is generally considered that a value higher than 10mIU/mL is immunity to hepatitis B, so the normal value is greater than 10mIU/mL. This antibody will generally decline gradually with time. gradually, and if it drops to about 10mIU/mL, it starts to lose immunity to hepatitis B. Therefore, in general, prevention should be advanced. When it drops below 100mIU/mL and is not lower than 10mIU/mL, the hepatitis B vaccination should be reinforced, and if it is already less than 10mIU/mL, the hepatitis B vaccination should be given throughout.