Test Overview

Hepatitis B tests are blood tests that show whether you have an active hepatitis B infection. The tests can also show if you had the infection in the past.

The tests look for different signs of infection:

  • Antigens, which are made by bacteria or viruses.
  • Antibodies, which are made by the
    body to fight infection.
  • Hepatitis B DNA, which is the virus’s genetic material.

Hepatitis antibodies can take weeks or months to develop. So
an infected person may test negative early in the infection.

Most common tests

The most common tests are:

  • Hepatitis B surface antigen. This antigen is
    the earliest sign of an active hepatitis B infection. It may be
    present before symptoms occur.
  • Hepatitis B surface antibody.
    The presence of this
    antibody means that the infection is at the end of its active stage and you are no longer contagious. You can’t pass the virus to others.
  • Hepatitis B e-antigen. This antigen is only
    present during an active hepatitis B infection.
  • Hepatitis B DNA testing. A high level of this DNA means that the virus is multiplying in your body and you are very
    contagious.

Other tests

These tests are not done as often:

  • Hepatitis B core antibody. This antibody appears about 1 month after the start of an
    active infection. It can be found in people who had an infection in the
    past. It is also present in those with long-term, or chronic, hepatitis B.
  • Hepatitis B core antibody IgM.
    This antibody shows that a hepatitis B infection has occurred within the last 6 months. It can also mean that a chronic hepatitis B infection has flared up again.
  • Hepatitis B e-antibody. This antibody shows that the active stage of
    a hepatitis B infection is almost over, and your risk of spreading the virus is
    a lot lower.
  • Hepatitis D antibody. This test shows whether you’re infected with the hepatitis D virus. This infection occurs only in
    people who are already infected with hepatitis B. It’s rare in the United States and Canada, except among people who inject illegal
    drugs and those who are often exposed to blood products.

Why It Is Done

Hepatitis B testing is done
to:

  • Find the type of infection and see if an infection has occurred recently or
    in the past.
  • Screen people who
    have a higher chance of getting or spreading hepatitis B. This includes doctors, dentists, and nurses.
  • Screen blood donors and donor organs
    to prevent the spread of hepatitis B.
  • Find out if a person has antibodies after getting a hepatitis B vaccination. Having antibodies means the vaccine worked.
  • Find out if hepatitis B is the cause of abnormal liver function tests.
  • See how well treatment of chronic
    hepatitis B is working.

How To Prepare

You don’t need to do anything special to prepare for this test.

Talk to your doctor if you have any concerns about the need for the test, its
risks, or how it will be done. 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.
  • Apply 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.

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

Risks

There is very little chance of a problem from having a blood sample taken.

  • You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. You can use a warm compress several times a day to treat this.

Results

Hepatitis B tests are blood tests that show whether you have an active hepatitis B infection. The tests can also show if you had the infection in the past.

Abnormal (positive)

Hepatitis B and D virus tests

Hepatitis B

Hepatitis B antibodies and/or
antigens are found. More tests may be needed to see if you
have an acute or chronic infection.

  • Hepatitis B surface antigen shows an active infection. If the test is positive
    for longer than 6 months, this means you have a chronic infection. You can spread
    the infection to others.
  • Hepatitis B surface antibody shows the end of active infection and means you are
    protected against hepatitis B for life. It also can show that you got a hepatitis B vaccination. In some cases, the test shows that you have antibodies and antigen. In this case you are still contagious.
  • Hepatitis B e-antigen shows an active
    infection. You can spread it to others.
  • Hepatitis B DNA means that you have a current
    infection.
  • Hepatitis B core antibody
    shows that you have been infected with hepatitis B. It does not tell the difference
    between a past or present infection.
  • Hepatitis B core antibody IgM shows that a hepatitis B infection has occurred
    within the last 6 months. It can also mean that a chronic infection has flared up.
  • Hepatitis B e-antibody shows a less active infection. You are less contagious but
    can still infect others.

Hepatitis D

Hepatitis D antibodies are found. You have hepatitis D.

What Affects the Test

Your doctor will talk with you
about anything that might keep you from having the test or that may change the
test results.

What To Think About

  • The presence of
    hepatitis B antibodies may mean that
    you had a vaccination and it worked. The
    hepatitis B vaccine protects against hepatitis D infection
    also.
  • Tests that show how well your liver is working are
    usually done along with hepatitis B tests. These may include tests that measure bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate
    aminotransferase.

  • In many
    states, some types of hepatitis infections must be reported to the local health
    department. The health department can then send out a warning to others who
    may have been infected. This includes people who are close
    contacts of someone with hepatitis B.

References

Other Works Consulted

  • Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.

Credits

ByHealthwise Staff
Primary Medical Reviewer Kathleen Romito, MD – Family Medicine
Adam Husney, MD – Family Medicine
Specialist Medical Reviewer W. Thomas London, MD – Hepatology

Current as ofMarch 3, 2017