The meaning of a reactive result for a hepatitis B test depends on the type of test performed, according to the Hepatitis B Foundation. The three most common blood tests detect the presence of hepatitis B surface antigens, hepatitis B surface antibodies or hepatitis B core antibodies.
In the hepatitis B surface antigen test, a reactive or positive result means that a person is currently infected with the hepatitis B virus, explains the Hepatitis B Foundation. Reactive results from the hepatitis B surface antibody test means that people are now immune to the virus because they have been infected in the past and their immune systems produced antibodies to fight the infection. For the hepatitis B core antibody test, a reactive or positive result can mean either that a person is currently infected with hepatitis B virus or have been some time in the test. A reactive result for this test can also be a false positive, meaning that the person has never been infected with the virus.