Hepatitis B Virus Test

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Test Overview

Hepatitis B virus tests look for substances in the blood that show a hepatitis infection is active, ongoing (chronic), or has occurred in the past. The tests look for antigens, antibodies, or genetic material (DNA) of the virus that causes hepatitis. It is important to identify the type of hepatitis virus causing infection to prevent its spread and begin the proper treatment immediately.

Hepatitis B virus (HBV) testing

HBV is transmitted through infected body fluids, including blood, semen, and vaginal fluids (including menstrual blood). It also can be transmitted from a pregnant woman to her child at or near the time of birth.

• Hepatitis B surface antigen (HBsAg) is one of the most frequently performed tests for HBV. This HBV antigen is the earliest indicator of an active hepatitis B infection. This antigen may be present before symptoms of an HBV infection are present. If this antigen level remains high for more than 6 months, then you will probably become a carrier of HBV, meaning you can transmit it to others throughout your life.
• Hepatitis B surface antibody (HBsAb) is also one of the most common tests for HBV. Usually this antibody appears about 4 weeks after HBsAg disappears and means that the infection is at the end of its active stage and you cannot pass the virus to others (you are no longer contagious). This antibody also protects you from getting HBV again in the future. The test is done to determine the need for vaccination; the antibody will be present after receiving the HBV vaccine series, showing that you have protection (immunity) from the virus. Occasionally your test may show that you have both the HBsAb and HBsAg antibodies; in this case, you are still contagious.
• Hepatitis B core antigen (HBcAg). Currently, there is no test to find this antigen.
• Hepatitis B core antibody (HBcAb) is an antibody to the hepatitis B core antigen. This antibody appears about 1 month after an active HBV infection. It can be found in people who had an infection in the past and in those with long-term (chronic) HBV. It usually is present for life.
• Hepatitis B core antibody IgM (HBcAbIgM) is also an antibody to the hepatitis B core antigen. It shows a recent infection in the last 6 months.
• Hepatitis B e-antigen (HBeAg) is an HBV protein that is only present during an active HBV infection. This test determines how contagious you are. Testing for this antigen can also be used to monitor the effectiveness of treatment for HBV.
• Hepatitis B e-antibody (HBeAb) shows that the active stage of the HBV infection is almost over and your risk of being contagious is greatly reduced. HBeAb is usually present during chronic HBV infections.
• HBV DNA testing finds genetic material (DNA) from the hepatitis B virus. Currently, quantitative HBV DNA tests are done. A high HBV DNA level means that the virus is multiplying in your body and you are very contagious. If you have a chronic HBV infection, an elevated viral DNA level means you are at an increased risk for chronic hepatitis and may want to consider treatment with medications. Testing for HBV DNA also is important to monitor the effectiveness of treatment for chronic HBV infection. HBV DNA testing is a more sensitive test than HBeAg (above) for detecting HBV in the blood.

Hepatitis B vaccine is available to prevent an HBV infection.

Hepatitis D virus (HDV) testing

Infection with the hepatitis D virus (HDV), or delta agent, occurs only in people who are already infected with the hepatitis B virus (HBV). Vaccination against hepatitis B will prevent hepatitis D infection. Hepatitis D infection is rare in the United States and Canada, except among people who inject illegal drugs and those who are frequently exposed to blood products. The hepatitis D test detects HDV antibodies. A positive test indicates only that you have been infected with HDV—it cannot distinguish between an acute or chronic infection. Another test, the HDV RNA test, is needed to determine whether you have an active HDV infection. It does not distinguish between an acute or chronic infection. However, this test currently is not available except in research settings.

Since hepatitis B infections can be spread through sexual contact, practice safe sex until your test results are returned.

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Last updated:	November 04, 2005
Author:	Jan Nissl, RN, BS
Reviewed By:	Patrice Burgess, MD - Family Medicine, W. Thomas London, MD - Hepatology
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer