Hepatitis A Virus Antibody

Hepatitis A is a viral infection of the liver. This tests for the presence of hepatitis A antibodies. Elevated levels reflect immunity either through previous vaccination or exposure to the illness.

More info on Hepatitis A:

Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus (HAV). It is one of several various causes of hepatitis, a condition characterized by inflammation and enlargement of the liver. This test detects antibodies in the blood that are produced by the immune system in response to a hepatitis A infection.

Hepatitis A is one of five "hepatitis viruses" identified so far, including B, C, D, and E, that are known to cause the disease. While hepatitis A can cause a severe, acute disease that typically lasts 1 to 2 months, it does not cause a chronic infection as do some of the other hepatitis viruses.

Hepatitis A is spread, most commonly, from person-to person through stool (fecal) contamination or by ingesting food or water contaminated by the stool of an infected person (a foodborne illness). Recognized risk factors for hepatitis A include close contact with an infected person, international travel, household or personal contact with a child who attends a child care center, household or personal contact with a newly arriving international adoptee, a recognized foodborne outbreak, men who have sex with men, and use of illegal drugs.

Although there are many causes of hepatitis, the symptoms remain the same. In hepatitis, the liver is damaged and unable to function normally. It cannot process toxins or waste products such as bilirubin for their removal from the body. During the course of the disease, bilirubin and liver enzyme levels in the blood can increase. While tests such as bilirubin or a liver panel can tell a healthcare practitioner that someone has hepatitis, they do not identify the cause. Antibody tests for hepatitis viruses may help determine the cause.

There are two different classes of hepatitis A antibody that may be tested, IgM and IgG. When a person is exposed to hepatitis A, the body first produces hepatitis A IgM antibodies. These antibodies typically develop 2 to 3 weeks after first being infected (and are detectable before the onset of symptoms) and persist for about 3 to 6 months. Hepatitis A IgG antibodies are produced within 1 to 2 weeks of the IgM antibodies and usually persist for life.

A vaccine that prevents hepatitis A has been available since 1995. Historically, infection rates varied cyclically, with nationwide increases every 10-15 years. However, according to the Centers for Disease Control and Prevention (CDC), hepatitis A rates have declined by more than 95% since the vaccine first became available. In 2015, the number of acute hepatitis A cases reported nationwide was an estimated 2,800.