Hepatitis B Virus Antibodies
You will be tested for to see if you have HBV if you have symptoms suggesting you might have a viral hepatitis infection or are likely to have been exposed to the Hepatitis B virus; if you have chronic liver disease (possibly due to some other cause), if you were born to a mother who was HBV positive or if you are being treated for HBV. If you have recently received the vaccine, you will have a different test to check you have responded to it.
A blood sample taken from a vein in your arm
No test preparation is needed
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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. This allows determination of whether a patient has an acute or chronic infection, past infection now cleared or simply whether or not vaccination has been successful. The following table gives an overview of what tests are used:
Test
Description
Use
Hepatitis B Surface antigen (HBsAg)
Protein present on the surface of the virus, present in both acute & chronic infections.
Used to screen for & detect infection – it is the earliest indicator of acute infection & may be present before symptoms appear. Also present in patients with chronic infection.
Hepatitis B surface antibody (anti-HBs)
Antibody produced in response to HBsAg: levels rise during recovery phase of infection
Indicates previous exposure to the HBV but virus no longer present and can’t be passed on. It also protects against future infection. Antibodies can also be acquired from vaccination. This antibody will be detected after successful vaccination.
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. Also used to detect past infection but now immune in combination with Anti-HBs.
Hepatitis B e Antigen (HBeAg)
Protein produced and released into the blood by actively replicating hepatitis B virus
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. If the virus is “in –hiding” the eAg will no longer be present in the blood. *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 B e antibody (Anti-HBe)
Antibody produced in response to the hepatitis B e 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 (DNA)
Can detect an active HBV infection; its primary use is to monitor antiviral therapy in patients with chronic HBV infections.
*Sometimes, HBV goes into “hiding” in the liver and other cells and does not produce new viruses that can infect others, or produces them in such low amounts that they cannot be found in the blood. People who have this form are said to be carriers. In other cases, the body continues to make viruses that can further infect the liver and can be spread to other people. In both these cases, HBsAg will be positive. The HBeAG and Anti-HBe tests help in this diagnosis
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When is it requested?
A test for anti-HBs is used to determine whether the vaccine has produced the desired level of immunity. If levels of the antibody are over 10 mIU/mL, the person has good protection against infection with HBV. In a patient with acute hepatitis, IgM anti-HBc and HBsAg are usually requested together to detect recent infection by HBV. In persons with chronic hepatitis, or with elevated ALT or AST, HBsAg and anti-HBc are usually done to see if the liver damage is due to HBV. If so, HBsAg and HBeAg are usually measured on a regular basis (every 6 months to a year), since in some people HBeAg (and, less commonly, HBsAg) will go away on its own. In those who are being treated for chronic HBV, HBeAg and HBV DNA can be used to determine whether the treatment is successful.
All donated blood is tested for the presence of the HBsAg before being distributed.
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What does the test result mean?
Hepatitis B results are often requested in combination with tests for other viruses and other markers of disease, depending on the reason for testing. The results therefore will be evaluated together. Not everyone will need to have all the tests described here, so it is helpful to know which tests your doctor is requesting for you and why.
The table below summarises some of the results and what they mean. It is not fully comprehensive but covers the majority of common 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 below
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
Negative
Negative/low positive
Positive
Positive
Negative
Positive
Acute infection, now resolving
Negative
Positive
Negative
Positive
Negative*
Positive
Infection resolved: immunity due to natural infection
Negative
Positive
Negative
Immunity due to vaccination
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 acute infection (seroconversion)
Negative
Negative
Positive
Positive
Negative*
Positive
Acute infection is resolving (convalescent)
Positive
Negative
Negative
Positive
Negative*
Positive
Chronic infection but low risk of liver damage – carrier state
Positive
Negative
Negative
Positive
Positive
Negative
Indicate active chronic infection – liver damage possible
* 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.
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Is there anything else I should know?
While the tests described above are specific for HBV, other liver function 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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If it is possible that I have an HBV infection, will I need to have all of these tests done?
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Should I have the HBV vaccine?
Yes. Unless there is something in your medical history to the contrary, it is prudent to have the series of vaccinations. In the UK pregnant women are routinely tested for infection and, if positive, immunoglobulin and vaccination of the newborn baby is offered. Periodic measurement of anti-HBs in persons who have developed immunity to HBV is not needed; even if their antibody level falls below 10 mIU/mL, they still appear to be protected if exposed to the virus.
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Can I test myself for immunity?
No. These tests must be performed by trained laboratory staff in an accredited laboratory.