Final answer:
The difference between surface antibodies (anti-HBs) and surface antigens (HBsAg) in Hep B serology is that antigens indicate an active infection, while the presence of antibodies suggests immunity from past infection or vaccination.
Step-by-step explanation:
The Hepatitis B (Hep B) serology tests are used to determine the presence of surface antigens and surface antibodies related to the Hep B virus. The surface antigens, known as HBsAg, are proteins found on the surface of the virus itself and are an indicator of active infection. When a person is infected, these antigens are present in the blood. On the other hand, surface antibodies, or anti-HBs, are produced by the immune system in response to the HBsAg. The presence of surface antibodies in the absence of the antigen indicates previous exposure to the virus or successful vaccination. A serology test for Hep B can determine an individual's immune status to the virus and whether an infection is current, past, or if the person is protected due to vaccination.