What Does a Positive Hepatitis A Antibody Test Mean?

When a blood test shows a positive result for hepatitis A antibodies, it indicates that the body has been exposed to the hepatitis A virus (HAV) at some point. However, understanding the implications of this result depends on the specific type of antibody detected—IgM or IgG.

IgM antibodies typically signal a recent infection. These antibodies appear shortly after initial exposure to HAV and usually remain in the bloodstream for about 3 to 4 months. Their presence suggests that the individual has contracted hepatitis A recently and their immune system is actively responding to the virus.

On the other hand, IgG antibodies indicate a past infection and long-term immunity. These antibodies generally develop 3 to 12 weeks after the IgM antibodies begin to fade. Once formed, IgG antibodies remain in the body for life, providing protection against future infections with the hepatitis A virus.

In cases where both IgM and IgG antibodies are present, it is usually interpreted as a sign of recent infection. This combination suggests that the immune response is transitioning from the acute phase to the development of long-term immunity.

Regardless of whether the positive result is due to IgM or IgG antibodies, monitoring liver function is essential. If liver function tests are normal, it may mean that the person had a past infection and has fully recovered—no treatment is necessary in such cases. However, if liver enzymes are elevated or liver damage is detected, liver-protecting treatments may be required. It is always recommended to consult with a healthcare provider to interpret the results accurately and determine the appropriate next steps.