Hepatitis A virus (HAV) test is a blood test that looks for proteins (antibodies) made by the body in response to the virus that causes hepatitis A. These proteins will be present in your blood if you have a hepatitis A infection now or have had one in the past. It is important to identify the type of hepatitis virus causing the infection to prevent it from spreading and to start the proper treatment.

HAV infection is spread through food or water that has been contaminated by the feces (stool) of an infected person.

• IgM anti-HAV antibodies indicate a recent infection with hepatitis A virus. IgM anti-HAV antibodies generally can be detected in the blood as early as 2 weeks after the initial HAV infection. These antibodies disappear from the blood 3 to 12 months after the infection.
• IgG anti-HAV antibodies mean that you have had a hepatitis A viral infection. About 8 to 12 weeks after the initial infection with hepatitis A virus, IgG anti-HAV antibodies appear and remain in the blood for lifelong protection (immunity) against HAV.

Hepatitis A vaccine is available to prevent an HAV infection. If you have had this vaccine and you have anti-HAV antibodies, this means the vaccination was effective.

Why It Is Done

Hepatitis virus testing is done to:

• Identify the type of hepatitis virus causing a hepatitis infection.
• Screen people (such as doctors, dentists, and nurses) who have an increased chance of getting or spreading hepatitis A.
• Screen potential blood donors and donor organs to prevent the spread of hepatitis A.
• Find out whether a person has antibodies after getting a hepatitis A vaccine. If you had this vaccine and you now have antibodies to the hepatitis A virus (anti-HAV antibodies) in your blood, this means the vaccination was effective (you are immune to hepatitis A).
• Find out if a hepatitis A infection is the cause of abnormal liver function tests.

How To Prepare

You do not need to do anything before you have this test.

Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?) .

How It Is Done

The health professional taking a sample of your blood will:

• Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
• Clean the needle site with alcohol.
• Put the needle into the vein. More than one needle stick may be needed.
• Attach a tube to the needle to fill it with blood.
• Remove the band from your arm when enough blood is collected.
• Put a gauze pad or cotton ball over the needle site as the needle is removed.
• Put pressure on the site and then put on a bandage.