Anti-HBs positivity is generally considered normal because it is a protective antibody. In the general population, anti-HBs positivity can also occur if the hepatitis B vaccine takes effect. This is called hepatitis B surface antibody and indicates that immunity to the hepatitis B virus has been acquired and it is impossible to be infected by the hepatitis B virus again in the future, so it is generally a better result. However, some people can also develop anti-HBs positivity after being infected with the hepatitis B virus, which is often accompanied by positive hepatitis B core and e antibodies, a sign that hepatitis B has been cured. Some people may also have genetic mutations of the hepatitis B virus, so that surface antigen is not detected, but surface antibodies can be detected. Therefore, for this group of people, a highly sensitive DNA test for the hepatitis B virus can be performed, and if the DNA of the hepatitis B virus is not detected, it is not a genetic variant.