Hepatitis A Virus Test

Test Overview

The hepatitis A virus test is a blood test that shows if you have a hepatitis A infection now or had it in the past.

The test looks for antibodies made by the body to fight the virus. They will be in your blood if you have a hepatitis A infection now or have had one in the past.

Hepatitis A IgM antibodies.

These can be found as early as 2 weeks after you are first infected. They disappear 3 to 12 months after the infection.

Hepatitis A IgG antibodies.

These appear 8 to 12 weeks after you are first infected. They stay in your blood and protect you from hepatitis A permanently.

Why It Is Done

You may need these tests if:

  • You have symptoms of hepatitis.
  • You may have been exposed to the hepatitis A virus. You have a greater chance of being exposed to the virus if you have been to a country where the disease is common, you work in a day care center, or you live with someone who has the disease.
  • You've had other tests that show you have liver problems.
  • You or your doctor wants to know if you are protected from getting the disease.

How To Prepare

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How It Is Done

A health professional uses a needle to take a blood sample, usually from the arm.

Watch

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

The test looks for antibodies made by the body to fight the virus. They will be in your blood if you have a hepatitis A infection now or have had one in the past.

If you are tested soon after you were infected with hepatitis A, the test may show that you don't have the disease even when you have it. This is because hepatitis A antibodies can take weeks to develop. They may not be in your blood yet.

Hepatitis A test

Negative:

No hepatitis A virus antibodies are found.

Positive:

Hepatitis A antibodies are found. You may need more tests to find out if you have an active infection now or a past infection that got better.

  • IgM antibodies are found if you have an active or a recent infection. These antibodies usually show up as early as 2 weeks after you become infected. They last for a few months after symptoms have gone away.
  • IgG antibodies are found if you had an infection in the past or have been vaccinated.

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