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Hepatitis B Screening Hepatitis B virus (HBV) antigens are proteins that appear in different areas of the virus.The basic blood test for hepatitis B consists of three screening tests: a hepatitis B surface antigen test, which determines whether a person currently has the infection; a hepatitis B core antibody test, which determines whether a person has ever been infected; and a hepatitis B surface antibody test, which determines whether a person has cleared the virus after infection, or has been vaccinated and is now immune to future infections.The body's immune response produces antibodies tailored to each type of antigen (surface antibody, core antibody, and e antibody), which can also be detected from a blood test.The hepatitis B core antibody screening test detects the presence of antibodies to the HBV core antigen.The hepatitis B surface antibody screening test detects the presence of antibodies the immune system produces to attack the virus.A positive hepatitis B surface antibody screening test means the person has lifetime immunity from hepatitis B (the Centers for Disease Control and Prevention [CDC], 2009).The screening test for hepatitis B surface antigens detects the presence of HBV in the blood.The antigens are detectable 4-10 weeks after exposure to HBV.Is the person currently infected with HBV?These are described below.

Hepatitis B Screening
Hepatitis B virus (HBV) antigens are proteins that appear in different areas of the virus. HBV has three antigens (surface, core, and e), some of which can be detected in the blood. The body’s immune response produces antibodies tailored to each type of antigen (surface antibody, core antibody, and e antibody), which can also be detected from a blood test. The basic blood test for hepatitis B consists of three screening tests: a hepatitis B surface antigen test, which determines whether a person currently has the infection; a hepatitis B core antibody test, which determines whether a person has ever been infected; and a hepatitis B surface antibody test, which determines whether a person has cleared the virus after infection, or has been vaccinated and is now immune to future infections. These are described below.

Is the person currently infected with HBV? The screening test for hepatitis B surface antigens detects the presence of HBV in the blood. The antigens are detectable 4–10 weeks after exposure to HBV. A positive test result means the person is currently infected and can pass the infection to others. Most adults who acquire HBV clear the virus within a few months, and their hepatitis B surface antigen test result will be negative after that time. Some people remain infected and continue to test positive for hepatitis B surface antigen. If, after 6 months, the person still tests positive, his or her HBV infection is considered chronic. People diagnosed with chronic hepatitis B should have an evaluation (see Chapter 3).

Has the person ever been infected with HBV? The hepatitis B core antibody screening test detects the presence of antibodies to the HBV core antigen. The antibody appears in the blood within a few weeks of HBV infection. A positive result means the person has been infected with HBV, but it does not specify whether the person has cleared the virus, still has the infection, or is immune to reinfection.

Is the person immune to HBV? The hepatitis B surface antibody screening test detects the presence of antibodies the immune system produces to attack the virus. These antibodies appear in people who have been vaccinated against HBV, or who had been infected and cleared the virus from their bodies. A positive hepatitis B surface antibody screening test means the person has lifetime immunity from hepatitis B (the Centers for Disease Control and Prevention [CDC], 2009). In some situations, hepatitis B screening may be unavailable, but the hepatitis B vaccine is available. People can be safely vaccinated against hepatitis B if they have been previously infected or vaccinated.