What laboratory findings would indicate an active Hepatitis A infection?

• A. anti-HAV + IgG
• B. anti-HAV + IgM
• C. HBsAg + HBeAg
• D. Anti-HBc + Anti-HBsAg

Answer: (B)

The presence of anti-HAV IgM indicates an active Hepatitis A infection. Immunoglobulin M (IgM) antibodies are produced by the immune system in response to a recent infection. In the context of Hepatitis A, these antibodies typically appear shortly after the onset of symptoms, making them a reliable marker for acute infection.

The interpretation of the other options is important for understanding why they do not indicate an active infection. Anti-HAV IgG signifies past infection or vaccination against Hepatitis A but does not reflect current active infection. HBsAg and HBeAg are markers associated with Hepatitis B, not Hepatitis A, indicating multiple avenues in viral hepatitis testing and the specificity needed when considering the type of hepatitis. Anti-HBc and Anti-HBsAg are also related to Hepatitis B, reflecting previous exposure or resolution rather than indicating an active Hepatitis A infection.

In summary, positive IgM antibodies against Hepatitis A virus specifically confirm an acute and active illness, distinguishing it from markers indicating past infections or different types of hepatitis viruses.