The hepatitis B immunity test, often referred to as a titer test, measures the presence of antibodies in your blood. This test is crucial for determining if you have developed immunity to the hepatitis B virus either through vaccination or recovery from a past infection.
Testing for evidence of immunity after vaccination is not routinely recommended, except those in certain groups. In those at risk of occupational exposure, particularly healthcare and laboratory workers, antibody levels should be checked one to two months after the completion of the full vaccination course.

Hepatitis B Surface Antibodies