HBsAb, the hepatitis B surface antibody, is a protective antibody. A positive HBsAb indicates that the body has developed immunity to the hepatitis B virus, but the specific situation needs to be combined with other indicators to determine. The intact hepatitis B virus is spherical in shape and consists of an envelope and a nucleocapsid, which contains HBsAg, glycoproteins and other components. After the hepatitis B virus invades the body, the body’s immune system will produce some substances to resist the virus. Hepatitis B surface antibody is exactly an antibody produced by the body’s immune system against the surface antigen of the hepatitis B virus, which is protective for us, and it can bind with the surface antigen of the hepatitis B virus to play a role in resisting the invasion of the hepatitis B virus. If our body’s immune system is powerful enough to produce enough indicated antibodies to neutralize the surface antigen, the hepatitis B virus that invades the body will be completely removed and the five tests for hepatitis B will show a negative hepatitis B indicated antigen and a positive hepatitis B surface antibody, core antibody and e antibody. In addition, the main component of the vaccine we use to prevent hepatitis B is hepatitis B surface antigen. After vaccination, the body’s immune system will also produce protective hepatitis B surface antibodies, so that the body has immunity against hepatitis B. At this time, the five tests for hepatitis B only show positive surface antibodies, and negative hepatitis B surface antigen, core antibodies and e antibodies. The HBsAb is a protective antibody produced by the body’s immune system against the hepatitis B virus, and a positive HBsAb indicates that the body has immunity against hepatitis B. People with negative HBsAb do not have this immunity and need to be vaccinated against hepatitis B to prevent infection with hepatitis B.