Hepatitis A Virus IgM

Function

The Hepatitis A Virus (HAV) IgM test is a serological assay used to detect IgM antibodies produced by the immune system in response to an acute infection with the Hepatitis A virus. IgM is the first antibody the body creates when it encounters a new infection, making this test the gold standard for diagnosing early-stage Hepatitis A.

Why it is Ordered

This test is primarily ordered when a patient presents with symptoms of acute viral hepatitis, such as:

• Jaundice (yellowing of the skin and eyes)
• Dark-colored urine and pale stools
• Severe abdominal pain, particularly in the upper right quadrant
• Fever, fatigue, and loss of appetite It is also used during outbreak investigations to identify recently infected individuals who may be spreading the virus through contaminated food or water.

Associated Conditions

Hepatitis A is a highly contagious liver infection caused by the HAV. Unlike Hepatitis B or C, it does not cause chronic liver disease and is rarely fatal, though it can cause debilitating symptoms and acute liver failure in rare cases (especially in older adults or those with pre-existing liver conditions). The presence of IgM antibodies confirms an active or very recent infection (typically within the last 6 months). Once the infection resolves, IgM levels fade, and IgG antibodies develop, providing lifelong immunity.