What Is Hepatitis B Core Antibody?

Hepatitis B core antibodies are primarily divided into two types: IgG and IgM. A positive IgM anti-hepatitis B core antibody result typically indicates an active viral infection, which may be contagious. On the other hand, a positive IgG anti-hepatitis B core antibody result usually signifies a past infection, and in most cases, the individual is no longer infectious.

Hepatitis B core antibodies generally become detectable in the blood 3 to 5 weeks after the hepatitis B surface antigen appears. Determining whether a positive core antibody result indicates an active or past infection requires a comprehensive evaluation of other hepatitis B test results, particularly the "two pairs and a half" panel.

Currently, most standard tests do not differentiate between IgG and IgM antibodies; they only indicate whether the core antibody is present or not. If all other hepatitis B markers are negative and only the core antibody is positive, this may suggest a past infection or a recovery phase where the surface antigen has cleared but the protective surface antibody has not yet developed. It could also indicate that the person is an asymptomatic carrier of the hepatitis B virus.

Therefore, a single positive core antibody result should be further evaluated with a hepatitis B virus DNA test to confirm the presence of active viral replication. If someone tests positive for only the core antibody and has no evidence of current infection, they may still benefit from receiving the hepatitis B vaccine. This can help stimulate the production of hepatitis B surface antibodies, which protect the body from future infection.

In summary, interpreting a positive hepatitis B core antibody result requires careful analysis alongside other diagnostic tests. Proper follow-up and consultation with a healthcare provider are essential for accurate diagnosis and appropriate management.