In a patient suspected of having acute hepatitis A, what is the best method for diagnosis?

The best method for diagnosing acute hepatitis A is through the detection of IgM antibodies specific to the hepatitis A virus (HAV). When a person is infected with HAV, their immune system responds by producing IgM antibodies, which typically appear early in the course of the infection, often within the first week of symptoms and can persist for up to 6 months. Testing for these IgM antibodies is thus a reliable marker for an acute infection.

While a liver biopsy could provide information about liver health, it is invasive and not necessary for diagnosing hepatitis A, especially when less invasive tests are available. An abdominal ultrasound can help assess the liver and rule out other conditions but also does not provide a definitive diagnosis for hepatitis A. A comprehensive hepatitis panel includes tests for various types of hepatitis viruses, but it may not specifically indicate acute hepatitis A as quickly or effectively as the quantification of IgM. Therefore, looking for IgM antibodies directly correlates with confirming an active infection of hepatitis A and is the preferred diagnostic method.