Hepatitis

There are several causes of hepatitis and the accompanying symptoms, so these tests are used to determine if symptoms are due to a current infection with a virus and to identify which virus in particular is causing the disease. These tests may also help determine if someone has been exposed to one of the viruses even before symptoms develop.

Hepatitis Assay typically consists of the following tests:

• Hepatitis A antibody, IgM—these antibodies typically develop 2 to 3 weeks after first being infected and persist for about 2 to 6 months. Hepatitis A IgM antibodies develop early in the course of infection, so a positive hepatitis A IgM test is usually considered diagnostic for acute hepatitis A in a person with signs and symptoms.
• Hepatitis B core antibody, IgM—this is an antibody produced against the hepatitis B core antigen. It is the first antibody produced in response to a hepatitis B infection and, when detected, may indicate an acute infection. It may also be present in people with chronic hepatitis B when flares of disease activity occur.
• Hepatitis B surface Ag—this is a protein present on the surface of the hepatitis B virus. It is the earliest indicator of an acute infection but may also be present in the blood of those chronically infected.
• Hepatitis C antibody—this test detects antibodies produced in response to an HCV infection. It cannot distinguish between an active or previous infection. If positive, it is typically followed up with other tests to determine if the infection is a current one. (See the article on Hepatitis C for more on this.)

There are some other tests that may be offered as part of a hepatitis panel, depending on the laboratory performing the tests.