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Hepatitis B

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; Acute Viral Hepatitis Panel; 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; if you are being treated for HBV

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

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 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:

  • Acute infection - presence of typical signs and symptoms with positive screening test
  • Chronic infection — persistent infection with the virus detected by lab tests accompanied by inflammation of the liver
  • 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)
  • "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 indicate 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. Since routine vaccination of children was implemented in 1990, the cases of acute hepatitis B have decreased by about 82%, according to the CDC.

How is the sample collected for testing?

A blood sample is drawn by needle from a vein in the arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.

The Test

How is it 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 is 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:

  • 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)
  • To diagnose chronic HBV hepatitis: HBsAg, hepatitis B virus (HBV) DNA, and sometimes HBeAg
  • 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
  • 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), and 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).

The following table summarizes the various hepatitis B tests and their uses:

Test Description Use
Hepatitis B surface antigen (HBsAG) Protein that is present on the surface of the virus; will be present in the blood with acute and chronic HBV infections Often used to screen for and detect HBV infections; earliest indicator of acute hepatitis B and frequently identifies infected people before symptoms appear; undetectable in the blood during the recovery period; it is the primary way of identifying those with chronic infections.
Hepatitis B surface antibody (anti-HBs) Antibody produced in response to HBV surface antigen; levels in the blood rise during the recovery phase. Used to detect previous exposure to HBV; can also be acquired from successful vaccination. This test is done to determine the need for vaccination (if anti-HBs is absent) or to determine if a person has recovered from an infections and is immune (cannot get the infection again).
Anti-hepatitis B core (anti-HBc), IgM IgM antibody to the hepatitis B core antigen (The hepatitis B core antigen is present only in infected liver cells; it cannot be detected in the blood.) First antibody produced after infection with HBV; used to detect acute infection
Anti-hepatitis B core (anti-HBc), Total Both IgM and IgG antibodies to hepatitis B core antigen Can be used to help detect acute and chronic HBV infections; it is produced in response to the core antigen and usually persists for life.
Hepatitis B e-antigen (HBeAG) Protein produced and released into the blood by actively replicating hepatitis B virus Unlike the surface antigen, the e-antigen is found in the blood only when the HBV virus is actively replicating. HBeAg is often used as a marker of ability to spread the virus to other people (infectivity). It may also be used to monitor the effectiveness of treatment. However, there are some types (strains) of HBV that do not make e-antigen; these are especially common in the Middle East and Asia. In areas where these strains of HBV are common, testing for HBeAg is not very useful.
Anti-hepatitis Be antibody (Anti-HBe) Antibody produced in response to the hepatitis Be antigen In those who have recovered from acute hepatitis B infection, anti-HBe will be present along with anti-HBc and anti-HBs. In those with chronic hepatitis B, anti-HBe can be used to monitor the infection and treatment.
Hepatitis B DNA (HBV DNA) Detects hepatitis B viral genetic material Can detect an active HBV infection; its primary use is to monitor antiviral therapy in patients with chronic HBV infections.

While the tests described above 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.

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When is it 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:

  • Fever
  • Fatigue
  • Loss of appetite
  • Nausea, vomiting
  • Abdominal pain
  • Dark urine
  • Pale stools
  • Joint pain
  • 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:

  • People who are possible source of infection through accidental cuts, needlesticks, etc. in health care workers
  • People born in areas of the world that have a greater than 2% prevalence of HbsAg (for example, much of Asia and Africa)
  • People born in the US but were not vaccinated and whose parents are from an area with greater than 8% prevalence of HbsAg
  • Men who have sex with men
  • People who have elevated liver enzymes (ALT and AST) with no known cause
  • People with certain medical conditions that require that their immune system be suppressed
  • Pregnant women
  • People who are in close contact with someone infected with HBV
  • 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.

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What does the test result mean?

The 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. Ask you doctor what she expects to find out from the results of your tests. She can help you understand what the results mean.

The table below summarizes possible interpretations of some common patterns of results.

Hep B surface antigen (HBsAg) Hep B surface antibody (Anti-HBs) Hep B core antibody (Anti-HBc IgM) Hep B core antibody Total (Anti-HBc IgG+IgM) Hep B e antigen (HBeAg)*See note Hep B e antibody (Anti-HBe) Interpretation / Stage of Infection
Negative Negative   Negative     No active or prior infection; not immune — may be good candidate for vaccine; possibly in the incubation stage
Positive Negative Negative Negative Positive Negative Early acute infection
Positive Negative Positive or Negative Positive or Negative Positive Negative Acute infection, usually with symptoms; contagious
Positive Negative Positive Positive Negative* Positive Late in the acute stage of infection (seroconversion)
Negative Negative Positive Positive Negative* Positive Acute infection is resolving (convalescent)
Positive Negative Negative Positive Positive Negative Usually indicates an active chronic infection (liver damage likely)
Positive Negative Negative Positive Negative* Positive Chronic infection but low risk of liver damage — carrier state
Negative Positive Negative Positive Negative* Positive Infection resolved (recovery); immunity due to natural infection
Negative Positive   Negative     Immunity due to vaccination

*Note: There are some types (strains) of HBV that do not make e-antigen. In areas where these strains of HBV are common (in the Middle East and Asia), testing for HBeAg is not very useful. In these cases, a negative HbeAg result does not necessarily mean that the antigen is not present or that the person is not infectious; it may be that the person is infected with a strain that does not make the e-antigen.

Hepatitis B viral (HBV) DNA: This test measures the amount of virus present in the blood, so results are reported as numbers, specifically, as "international units per milliliter." A high result usually means that the virus is actively replicating and that the infection can be passed to others. It also indicates that the person has a high risk of having liver damage.

A low result or one that is reported as below a lower limit (for example, 100 international units/milliliter) means the virus is not present or is present in such low numbers that it cannot be detected. This usually means that the infection cannot be spread to others. If the test is used to monitor treatment, a low result usually indicates the therapy is effective.

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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.

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Common Questions

1.  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.

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2.  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.

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3.  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 forms of 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.

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Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

Henry's Clinical Diagnosis and Management by Laboratory Methods. 21st ed. McPherson RA and Pincus MR, eds. Philadelphia: 2007, Pp 271-272.

Clarke, W. and Dufour, D. R., Editors (2006). Contemporary Practice in Clinical Chemistry. AACC Press, Washington, DC, Pp 273-275, 491-492.

American Association for the Study of Liver Diseases Practice Guidelines, Chronic Hepatitis B: Update 2009. PDF available for download at http://publish.aasld.org/practiceguidelines/Documents/Bookmarked%20Practice%20Guidelines/Chronic_Hep_B_Update_2009%208_24_2009.pdf through http://publish.aasld.org. Accessed January 2010.

Centers for Disease Control and Prevention (Reviewed July 8, 2008). Hepatitis B information for Health Professionals. Available online at http://www.cdc.gov/hepatitis/HBV/index.htm through http://www.cdc.gov. Accessed January 2010.

Centers for Disease Control and Prevention (July 19, 2008). Hepatitis B FAQs for the Public. Available online at http://www.cdc.gov/hepatitis/B/bFAQ.htm#overview through http://www.cdc.gov. Accessed January 2010.

Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Burtis CA, Ashwood ER, Bruns DE, eds. St. Louis: Elsevier Saunders; 2006, Pp 1805-1806, 1809-1811.

(Revised January 6, 2010) Hepatitis B Foundation, Diagnosis and Management. Available online at http://www.hepb.org/diagnosis/index.htm through http://www.hepb.org. Accessed January 2010.

ArupConsult. Hepatitis B Testing and Testing Algorithm. Available online at http://www.arupconsult.com/Topics/InfectiousDz/Viruses/HBV.html# through http://www.arupconsult.com and PDF available for download at http://www.arupconsult.com/Algorithms/HBV.pdf. Accessed January 2010.

MedlinePlus Medical Encyclopedia. Hepatitis B. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/000279.htm. Accessed January 2010.

Sources Used in Previous Reviews

Clinical Chemistry: Principles, Procedures, Correlations. Michael L. Bishop, Janet L. Duben-Engelkirk, Edward P. Fody. Lipincott Williams & Wilkins, 4th Edition.