The symptoms of hepatitis B can be signs of many different illnesses. Before arriving at a hepatitis B diagnosis, a doctor must first conduct blood tests to check for the presence of HBV-specific antibodies and antigens, specialized immune proteins that help the body fight infection. The type of immune proteins present in the body can reveal whether or not a patient is infected, and to what extent the body was able to fight off the infection.
According to the CDC, the following are the immune proteins associated with HBV infection:
- Hepatitis B surface antigen (HBsAg), which is found on the surface of HBV and indicates contagious acute or chronic HBV infection.
- Hepatitis B surface antibody (anti-HBs), which is typically produced when the body has fought the HBV virus and become immune to it.
- Total hepatitis B core antibody (anti-HBc), which indicates infection with HBV but does not differentiate between past and present infection.
- IgM antibody to hepatitis B core antigen (IgM anti-HBc), which indicates acute infection with HBV.
Individuals acutely infected with HBV will be:
- positive for the HBsAg, anti-HBc, and IgM anti-HBc and
- negative for anti-HBs.
Individuals chronically infected with HBV will be:
- positive for HBsAg and anti-HBc and
- negative for IgM anti-HBc.
Individuals immune to HBV infection due to hepatitis B vaccination will be:
- positive for anti-HBs and
- negative for HBsAg and anti-HBc.
Individuals immune to HBV infection due to natural HBV infection will be:
- positive for anti-HBc and anti-HBs and
- negative for HBsAg.