Testing is the key

Your doctor can perform tests that will indicate whether you have been exposed to or have become infected with hepatitis A, B, or C. Keep in mind that getting tested and treated is the key to avoiding serious liver disease.

To determine if you have been infected with the hepatitis A virus, your doctor will perform tests that look at several things:

• Liver function. When the liver is not working well, a blood test will show higher than normal levels of liver enzymes. (An enzyme is a substance that speeds up chemical reactions in the body.) The key marker of hepatitis is an elevation of the liver enzyme alanine aminotransferase, or ALT. But since other things can cause an elevation in ALT, your doctor must confirm that hepatitis is responsible for raising your ALT. He or she does this by looking for antibodies produced against the hepatitis A virus.

• Antibodies. Antibodies are produced by the immune system in response to foreign substances, like the hepatitis A virus. Your doctor will conduct blood tests to detect the presence of antibodies produced against the hepatitis A virus. If found, this is a strong indicator that you were exposed to the virus.

A positive hepatitis A test indicates a recent infection, or it may indicate that you have developed immunity to the virus due to a prior infection.

To determine if you have been infected with the hepatitis B virus, your doctor will perform several tests that look at different things:

• Liver function. When the liver is not working well, a blood test will show higher than normal levels of liver enzymes. (An enzyme is a substance that speeds up chemical reactions in the body.) The key marker of hepatitis is an elevation of the liver enzyme alanine aminotransferase, or ALT. But since other things can cause an elevation in ALT, your doctor must confirm that hepatitis is responsible for raising your ALT levels.

• Traces of the virus. The hepatitis B virus has an outer protein coat. Doctors can look for pieces of this protein coat and test for HbsAg (hepatitis surface antigen). If results of this test are positive, you either have acute or chronic hepatitis B, or are a carrier.

• Antibodies. Antibodies are produced by the immune system of the body in response to foreign substances, like the hepatitis B virus. Doctors use a test called ELISA (enzyme-linked immunosorbent assay) to detect antibodies that have been produced specifically against the hepatitis B virus. This is a strong indicator for exposure to the virus.

• Liver biopsy. Doctors remove a small piece of the liver and examine it under a microscope. This is the best way to assess the amount of liver damage that has occurred.

These tests for hepatitis B can indicate (1) whether you are infected, (2) if you are recovering from the disease, (3) if you have a chronic infection, or (4) if you are immune to hepatitis B.

To determine if you have been infected with the hepatitis C virus, your doctor will perform several tests that look at different things:

• Liver function. When the liver is not working well, a blood test will show higher than normal levels of liver enzymes. (An enzyme is a substance that speeds up chemical reactions in the body.) The key marker of hepatitis is an elevation of the liver enzyme alanine aminotransferase, or ALT. But since other things can cause an elevation in ALT, your doctor must confirm that hepatitis is responsible for raising your ALT levels.

• PCR test. Doctors use the PCR (polymerase chain reaction), HCV RNA (ribonucleic acid), or viral load tests to look for genetic material that belongs to the virus. These tests measure the amount of virus you have.

• Antibodies. Antibodies are produced by the immune system of the body in response to foreign substances, like the hepatitis C virus. Doctors use a test called ELISA (enzyme-linked immunosorbent assay) to detect antibodies that have been produced specifically against the hepatitis C virus.

• Liver biopsy. In this procedure, doctors remove a small piece of the liver and examine it under a microscope. This is the best way to assess the amount of liver damage that has occurred.

These tests will show if you are infected with the hepatitis C virus or if you were infected in the past.