Hepatitis B Test
Also known as: HBV; Hep B; anti-HBs; Hepatitis B surface antibody; HBsAg; Hepatitis B surface antigen; HBeAg; Hepatitis B e antigen; anti-HBc; Hepatitis B core antibody; anti-HBc, IgM; anti-HBe; Hepatitis B e antibody; HBV DNA
Formal name: Hepatitis B virus
Related tests: Hepatitis A; Hepatitis C; Liver panel; Bilirubin; AST; ALT; GGT
At a Glance
Why get tested?
To detect, diagnose, and/or follow the course of an infection with hepatitis B virus (HBV) or to determine if the vaccine against hepatitis B has produced the desired level of immunity.
When to get tested?
If you have symptoms of a hepatitis B infection or are likely to have been exposed to the hepatitis B virus; if you have chronic liver disease due to some other cause; if you have received the hepatitis B vaccine; or if you are being treated for HBV.
Sample required
A blood sample drawn from a vein in your arm
Is any test preparation needed?
No preparation is needed.
The Test Sample
What is being tested?
Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). It is one of several various causes of hepatitis, a condition characterized by inflammation and enlargement of the liver.Other causes of hepatitis include, for example, certain drugs, inherited disorders and autoimmune diseases. HBV is one of five hepatitis viruses identified so far. The other four are A, C, D, and E.
HBV is the most common cause of acute hepatitis and the most widespread cause of chronic viral infections worldwide (although hepatitis C virus is a more common cause in most of North America and Europe). According to the Centers for Disease Control and Prevention (CDC), there were about 43,000 new cases of hepatitis B in 2007 in the U.S. However, that number is only an estimate--the actual number of cases that were reported was much lower because many people have few or mild symptoms and never know they have the disease. The chronic form of hepatitis B continues to be a problem in the U.S. with about 800,000 to over 1 million people affected. Worldwide, it is thought to affect about 350 million people and to be a factor in the death of about 620,000 each year.
HBV is spread through contact with blood or other body fluids from an infected person. Exposure can occur, for example, through sharing of needles for IV drug use or through unprotected sex. People who live in or travel to areas of the world where hepatitis B is prevalent are at a greater risk. Mothers can pass the infection to their babies, usually during or after birth. The virus, however, is not spread through food or water, casual contact such as holding hands, or coughing or sneezing.
The course of HBV infections can vary from a mild form that lasts only a few weeks to a more serious chronic form lasting years. Sometimes chronic HBV leads to serious complications such as cirrhosis or liver cancer. Some of the various stages or forms of hepatitis B include:
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Acute infection—presence of typical signs and symptoms with positive screening test
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Chronic infection—persistent infection with the virus detected by lab tests accompanied by inflammation of the liver
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Carrier (inactive) state—persistent infection but no liver inflammation; a carrier is someone who may appear to be in good health but harbors the virus and can potentially infect others
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“Cleared” infection—no longer any evidence of infection; viral antigen and DNA tests are negative and no signs or symptoms of liver inflammation (although, in many cases, the virus is present in an inactive state in the liver)
The signs and the symptoms of an acute hepatitis B infection can be very similar to those of other types of acute hepatitis. Some of these include fever, tiredness, nausea, vomiting and jaundice. With hepatitis, the liver is damaged and is not able to function normally. It cannot process toxins or waste products such as bilirubin for their removal from the body. During the course of disease, bilirubin and liver enzyme levels in the blood may increase. While tests such as bilirubin or a liver panel can tell your doctor that you have hepatitis, they will not tell her what is causing it. Tests that detect infection with a hepatitis virus may help determine the cause.
There are several different tests that can be used to detect current or previous HBV infection. Some of the tests detect antibodies produced in response to HBV infection; some detect viral antigens while others detect viral DNA. They can be used to screen for infection in the absence of symptoms, to determine whether infection is acute or chronic, or to monitor a chronic infection.
Though a potentially serious infection, acute HBV infection usually resolves on its own in most adults. Infants and children tend to develop a chronic infection more often. A vaccine is available to help prevent hepatitis B. According to the CDC, since routine vaccination of children was implemented in 1990, the cases of acute hepatitis B have decreased by about 82%.
How is the sample collected for testing?
A blood sample is drawn by needle from a vein in the arm.
The Tests
How are the tests used?
Hepatitis B tests may be used for a variety of reasons. Some of the tests detect antibodies produced in response to HBV infection; some detect antigens produced by the virus and others detect viral DNA.
Generally, one set of tests are used to determine the cause of acute symptoms while another set of tests may be used after a diagnosis is made, to monitor possible progression of the disease, to detect chronic infection and/or carrier status.
The items below list the main uses for HBV tests:
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To detect acute hepatitis B infection: hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc), IgM and sometimes hepatitis B e antigen (HBeAg)
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To diagnose chronic HBV hepatitis: HBsAg, hepatitis B virus (HBV) DNA, and sometimes HBeAg
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To monitor chronic hepatitis B infection and its treatment: HBsAg, hepatitis B e antigen (HBeAg), hepatitis B surface antibody (anti-HBs) IgG, hepatitis B e antibody (anti-HBe) IgG and HBV DNA
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To detect previous exposure to hepatitis B, in a person who is immune compromised (when the virus can become reactivated): hepatitis B core antibody (anti-HBc) total and anti-HBs
Some of the secondary reasons to perform testing include, to screen for hepatitis B infection in at-risk populations or in blood donors, to determine if someone is a carrier, to detect previous infection (with subsequent immunity), to determine if immunity has developed due to vaccination.
Some of the tests used to screen for infection may be performed as part of an acute viral hepatitis panel in conjunction with tests for other hepatitis viruses including hepatitis A (HAV) or hepatitis C (HCV).
While the tests are specific for HBV, other liver tests such as AST, ALT, and gamma-glutamyl transferase (GGT) may be used to monitor the progress of the disease. In some cases, a liver biopsy may be performed for confirmation.
When are hepatitis B tests ordered?
Hepatitis B tests may be ordered when someone has signs and symptoms associated with acute hepatitis to determine if they are due to infection with HBV. Some of these include:
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Fever
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Fatigue
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Loss of appetite
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Nausea, vomiting
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Abdominal pain
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Dark urine
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Pale stools
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Joint pain
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Jaundice
Hepatitis B tests may be done as follow up when routine tests results such as ALT and/or AST are elevated. Sometimes acute forms of hepatitis may be detected this way since they may cause only mild symptoms that can be confused with the flu. Chronic hepatitis more often has no symptoms and is more commonly detected when routine test results are abnormal.
A test for hepatitis B surface antigen (HBsAg) may be used for screening when someone falls into one of the high-risk categories for chronic hepatitis B. In September 2008, the CDC revised it guidelines and recommends the following groups be tested for HBsAg:
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People who are possible source of infection through accidental cuts, needlesticks,etc in healthcare workers
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People born in areas of the world that have a greater than 2% prevalence of HbsAg (for example, much of Asia and Africa)
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People born in the US but were not vaccinated and whose parents are from an area with greater than 8% prevalence of HbsAg
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Men who have sex with men
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People who have elevated liver enzymes (ALT and AST) with no known cause
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People with certain medical conditions that require that their immune system be suppressed
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Pregnant women
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People who are in close contact with someone infected with HBV
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Those infected with HIV
In addition, some states in the US recommend that people who are in contact with the public and who are a possible source of infection through accidental cuts, scrapes, etc. be screened.
When hepatitis B tests are used to monitor people with chronic hepatitis B infections, they may be performed on a regular basis. Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) are usually measured about every 6 months to a year, since in some people HBeAg (and, less commonly, HBsAg) will go away on their own. In those who are being treated for chronic HBV, HBeAg and HBV DNA can be used to determine whether the treatment is successful. HBV DNA will fall, usually to undetectable levels, with successful treatment. If HBeAg was positive before treatment and becomes negative, then treatment may sometimes be stopped after a further period of treatment, and both it and HBV DNA may remain undetectable. If HBeAg was negative before treatment or remains positive, then treatment is usually continued.
All donated blood is tested for the presence of the HBsAg before being distributed for transfusion.
Hepatitis B surface antibody (anti-HBs): a positive result indicates immunity to hepatitis B from the vaccination or recovery from an infection.
What do the test results mean?
Tests for hepatitis B may be ordered individually but are often ordered in some combination depending on the reason for testing. Results of the tests are typically evaluated together. Sometimes the meaning of one result depends on the result of another test. However, not all tests are done on all people. Your doctor can help you understand what the results mean.
Is there anything else I should know?
Even if you don’t have symptoms, an HBV infection can damage your liver and you can spread the infection to others. For this reason, it is important to get tested if you think you have been exposed to HBV.
Hepatitis D (HDV) is another virus that can cause liver infections but only if hepatits B is also present. A person may become infected with both viruses at the same time (a co-infection) or may first be infected with hepatitis B and then become infected with HDV (a superinfection). In the U.S., the incidence of HDV is low. There is no vaccine for HDV but since it causes infections only in the presence of HBV, it may be prevented with the HBV vaccine.
Common Questions
If it is possible that I have an HBV infection, will I need to have all of these tests done?
No. Your doctor will determine which test(s) will be appropriate for your symptoms and history.
Should I get the HBV vaccine?
Yes. Unless there is something in your medical history to the contrary, it is prudent to get the series of vaccinations. Babies, children and adolescents are routinely given the series of shots. The Centers for Disease Control and Prevention recommends that adults in high risk groups get vaccinated. Some of these groups include those in close contact with someone who has hepatitis B, dialysis patients, people with chronic liver or kidney disease, people with HIV or who seek treatment for other sexually transmitted diseases or drug treatment and those who travel to countries where hepatitis B is common.
How is hepatitis B treated?
There is no specific treatment for acute hepatitis B infections. Symptoms are usually treated with supportive care. This usually involves making sure that you are getting plenty of rest and enough fluids and nutrition by eating and drinking small amounts several times a day.
Chronic hepatitis B may be treated with antiviral medications such as interferon, entecavir, tenofovir, lamivudine and adefovir. However, some antiviral drugs can have serious side effects and not all people need to be treated. Often, people with chronic hepatitis will be closely monitored to see if they develop cirrhosis or liver cancer. It is important to talk to your doctor about your treatment options and the risks and benefits of those currently available.
This article was last reviewed in March 2010. | This page was last modified in April 2010.
