At a Glance
Why Get Tested?
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
A blood sample drawn from a vein in your arm
Test Preparation 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 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.
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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.