What Does a Positive Hepatitis B Surface Antibody Mean?

A positive hepatitis B surface antibody (HBsAb) test indicates that the individual has developed antibodies against the hepatitis B virus (HBV). These antibodies are of the protective type and help defend the body against potential HBV infections. The presence of these antibodies is typically the result of successful vaccination with the hepatitis B vaccine, which stimulates the immune system to produce this protective response.

In some cases, individuals who have recovered from an acute hepatitis B infection may also develop surface antibodies, usually six months or more after the initial infection. This suggests that the body has effectively cleared the virus and is now immune to future infections.

On the other hand, if the hepatitis B surface antibody test is negative, it may indicate that the person lacks immunity to the virus. In such cases, it is generally recommended to receive the hepatitis B vaccine to develop protective immunity. The standard vaccination schedule involves three doses of recombinant yeast-derived hepatitis B vaccine administered at 0, 1, and 6 months. Adults typically receive a 20μg dose, while children receive a 10μg dose.

After the third dose of the vaccine, it is advisable to wait 1–2 months before testing for the presence of surface antibodies. If the antibody level reaches at least 10mIU/mL, it is considered a successful immune response, indicating that the individual is protected against hepatitis B. This level of response confirms that the vaccine has been effective in triggering the immune system to defend against the virus.