Hepatitis B Virus

Other names: HBV

The hepatitis B test is used to test for the presence of antibodies, which are produced when the body is exposed to the hepatitis B virus. Hepatitis B is a viral infection, which affects the liver, causing inflammation and sometimes severe damage. There is a vaccine against hepatitis B and the test may be used to see if the body has manufactured antibodies in response to the vaccine; if the test is positive, this means that the vaccine has worked. Hepatitis B is passed from person to person via transfer of bodily fluids; it is possible to pass it on via unprotected sexual intercourse or using needles, which have been used by an infected person.

When is the test used?

There are many different tests which are used to test for the presence of hepatitis B antibodies. The most common test is the hepatitis B surface antibody test (anti-HBs), which can determine whether a patient has been exposed to a hepatitis infection in the past. Other tests include hepatitis B surface antigen test and hepatitis B e-antigen test; antigens are foreign proteins, which enter the body.

The tests are usually ordered to see if the vaccine has worked and the patient is protected; however, they are also used to diagnose the infection and monitor the condition of a patient with an infection.

If the patient has symptoms of acute hepatitis B, IgM anti-HBC and HBsAg are usually ordered. If a patient has chronic hepatitis, HBsAg and HBeAg will usually be ordered; if the results show that the patient has liver damage caused by hepatitis B, the tests will be repeated on a regular basis to enable doctors to monitor their condition.

How is the test performed?

The test is done by taking a sample of blood from a vein in the patient’s arm; a needle is inserted into the vein and the blood is collected in a syringe. Once the sample has been collected, it will be bottled, labelled and sent away to the laboratory for testing.

What do the test results show?

The results of different tests will be used to reach a diagnosis, as follows:

  • Hepatitis B surface antibody (anti-HBs): if the test result is positive, this indicates that the vaccine has worked and the individual is immune from the virus.
  • Hepatitis B surface antigen (HBsAg): if the test result is negative, this means that the patient has recovered from an infection; if the result is positive, this means the patient has an active infection.
  • Hepatitis B e-antigen (HBeAg): a positive result means that the infection can be passed onto other people, while a negative result usually means that the infection cannot be passed onto others.
  • Anti-hepatitis B core antigen: if the result is positive and the patient’s anti-HBs test is also positive, this usually indicates that the patient has recovered from the infection and is not a carrier.
  • HBV DNA: if the result is positive, this usually indicates that the infection can be passed onto other people, while a negative result usually indicates that the infection cannot be passed onto others.

Specific Blood Tests

Blood Test Guide

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