Acute Viral Hepatitis Testing
A blood sample taken from a vein in your arm
An acute viral hepatitis panel is a group of tests often performed together to detect a viral hepatitis infection. Hepatitis is a condition characterised by inflammation and enlargement of the liver. It has many different causes including, for example, drugs and autoimmune diseases, but a common cause is infection with a virus. There are five hepatitis viruses identified so far that can cause the disease, including Hepatitis A, B, C, D, and E. Viral hepatitis is most commonly caused by Hepatitis A, B, or C. Cytomegalovirus (CMV) and Epstein-Barr virus (EBV) can also cause hepatitis.
Regardless of cause, the signs and symptoms of hepatitis are the same. If acute symptoms are suspected to be caused by one of the hepatitis viruses or if someone is at an increased risk of being infected or has been exposed, then hepatitis testing can help determine if the person has been infected and which virus is present.
Hepatitis A virus (HAV) is highly contagious and is usually contracted by ingesting food or water contaminated with the virus or by coming in direct physical contact with an infected person. While Hepatitis A is usually mild, it can on rare occasions cause a severe, acute disease; however, it does not cause a chronic infection as do Hepatitis B and C. A vaccine is available to prevent Hepatitis A.
Hepatitis B virus (HBV) is the most common cause of acute viral hepatitis. It is spread through contact with blood or other body fluids from an infected person. Exposure can occur, for example, through sharing of needles for intravenous 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 birth. The virus, however, is not spread through food or water, casual contact such as holding hands, or coughing or sneezing. A vaccine can be given to protect against Hepatitis B.
Hepatitis C virus (HCV) is also spread by exposure to contaminated blood, primarily though the sharing of needles by intravenous drug users, but also by sharing personal items contaminated by blood such as razors, through unprotected sex with an infected person, via health care occupational exposure, and from mother to baby during childbirth. Before tests for HCV became available in the 1990s, HCV was often transmitted by blood transfusions but this is now extremely rare. Currently, there is no vaccine to prevent infection with HCV.
An acute viral hepatitis panel includes tests that can detect an infection caused by one of these three viruses. It typically includes:
- Hepatitis A antibody, IgM
- Hepatitis B core antibody, IgM
- Hepatitis B surface Ag
- Hepatitis C antibody
Some of the tests detect IgM antibodies. These are the first antibodies produced during the initial stages of infection. As the disease progresses or resolves, IgM antibody levels decrease. Another test frequently performed measures hepatitis B surface antigen (HBsAg), which detects proteins on the surface of the virus. HBsAg is the earliest indicator of an acute Hepatitis B infection and is usually present even before symptoms appear, so this test is useful for screening those who are at high risk of infection or who may have been exposed. A test for Hepatitis C antibody cannot distinguish between an active or previous infection and further testing is necessary (e.g. molecular detection of HCV RNA) to determine whether the infection is current.
How is the sample collected for testing?
A blood sample is obtained by inserting a needle into a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
How is it used?
An acute hepatitis panel of tests is used to help detect and/or diagnose an acute liver infection due to one of the three most common hepatitis viruses: Hepatitis A virus (HAV), Hepatitis B virus (HBV), or Hepatitis C virus (HCV). There are several causes of hepatitis and the accompanying symptoms, so these tests are used to determine if symptoms are due to a current infection with a virus and to identify which virus in particular is causing the disease. These tests may also help determine if someone has been exposed to one of the viruses even before symptoms develop. An acute hepatitis panel typically consists of the following tests:
- Hepatitis A antibody, IgM—If you are exposed to Hepatitis A, your body will first produce Hepatitis A IgM antibodies. These antibodies typically develop 3 to 4 weeks after first being infected and persist for about 2 to 6 months. Hepatitis A IgM antibodies develop early in the course of infection, usually about a week after the first symptoms appear, so a positive Hepatitis A IgM test is usually considered diagnostic for acute Hepatitis A.
- Hepatitis B core antibody, IgM—This is an antibody produced against the Hepatitis B core antigen. It is the first antibody produced in response to a Hepatitis B infection and, when detected, may indicate an acute infection. It may also be present in people with chronic hepatitis B when flares of disease activity occur.
- Hepatitis B surface Ag—This is a protein present on the surface of the Hepatitis B virus. It is the earliest indicator of an acute infection but may also be present in the blood of those chronically infected.
- Hepatitis C antibody—This test detects antibodies produced in response to an HCV infection. It cannot distinguish between an active or previous infection. If positive, it is typically followed up with other tests (including molecular detection of HCV RNA) to determine is the infection is a current one.
There are some other tests that may be offered, depending on the laboratory performing the tests. These include:
- HAV antibody, total and HBV core antibody, total—These tests detect both IgM and IgG antibodies and may be used to determine if someone has had a previous infection.
- HBV surface antibody—This test may be used to help determine if an infection has resolved or if a person has developed the antibody after receiving the hepatitis B vaccine and achieved immunity for protection against HBV.
- HBV e antigen and antibody – These tests are usually only performed once a person has been confirmed as being infected with HBV. They can give an indication of how infectious a person with HBV infection may be (those with hepatitis B e antigen (HBeAg) are likely to be more infectious than those with hepatitis B e antibody (anti-HBe).
- HBV DNA – These tests are usually only performed once a person has been diagnosed with HJBV infection and can determine if a person has current active infection with HBV and how infectious they are likely to be.
EBV is typically associated with Glandular Fever, but can also cause hepatitis. Antibody tests are used to diagnose EBV infection.
When is it requested?
Acute viral hepatitis testing may be requested when a person has had blood tests which reveal abnormal liver function or and/or when someone has acute symptoms associated with liver damage such as:
- Fever, fatigue
- Loss of appetite
- Nausea, vomiting, abdominal pain
- Dark urine and/or pale coloured stool
- Joint pain
- Itching (pruritus)
In the presence of acute symptoms such as those listed above, a positive result is considered diagnostic for an acute infection with Hepatitis A and B. Testing acute viral hepatitis may sometimes be used to screen people who are at an increased risk for Hepatitis B or C infection or if it is known that they have been exposed. Below are listed some examples of who may be screened for acute viral hepatitis:
- People who have elevated liver enzymes (ALT and AST) with no known cause
- People who inject illegal drugs
- People with sexually transmitted diseases
- Men who have sex with men
- People with certain medical conditions that require that their immune system be suppressed (for example, transplant recipients)
- People who are in close contact with someone infected with Hepatitis B or C
- Those infected with HIV
- People who received a blood transfusion or organ transplant before July 1992 or clotting factor produced before 1987
- People on long-term dialysis
- Children born to Hepatitis B or C positive women
- For hepatitis B, people who were born in areas of the world where the virus is common, which includes Asia, Africa, southern Europe and parts of South America
- People with evidence of chronic liver disease
What does the test result mean?
The table below summarises results that may be seen following testing for acute viral hepatitis:
Anti-hepatitis A, IgM Hepatitis B surface antigen Anti-hepatitis B core, IgM Anti-hepatitis C Interpretation Positive Negative Negative Negative Acute hepatitis A Negative Positive Positive Negative Acute hepatitis B* Negative Positive Negative Negative Chronic hepatitis B infection Negative Negative Positive Negative Quantity of hepatitis B surface antigen is too low to detect Negative Negative Negative Positive Acute or chronic hepatitis C; additional tests are required to make the determination
* Note – Persons with small amounts of anti-hepatitis B core IgM in their blood are more likely to have chronic HBV infection of have been infected with HBV several months previously.
If other hepatitis tests are performed to help determine prior exposure or previous infection, they may indicate the following:
- Hepatitis A antibody, total (IgM and IgG) — if negative, no current or previous HAV infection; if positive, indicates exposure to HAV or the HAV vaccine. An IgM test must be done if an acute infection is suspected.
- Hepatitis B core antibody, total (IgM and IgG) — a positive test can indicate previous exposure to the virus. An IgM test must be performed if an acute infection is suspected.
- Hepatitis B surface antibody — if positive, it indicates that a HBV infection has resolved; depending on results of other HBV tests. A negative result may indicate that an infection has not resolved if hepatitis B surface antigen is positive. It will also be positive with a negative hepatitis B core antibody after you have received a hepatitis B vaccine.
It is possible to be infected with more than one hepatitis virus, and an acute infection with one hepatitis virus can be superimposed on a chronic infection with a different hepatitis virus. In such cases, there may be a positive result for more than one type of virus and care must be taken when interpreting the results.
If all the viral tests are negative, then the antibody or antigen level is too low to detect or the hepatitis is due to some other cause. For more on this and other tests that may be done to determine the cause, see the article on Hepatitis.
Is there anything else I should know?
The test results may not always be able to tell whether you have had a previous hepatitis infection or whether you have developed antibodies in response to a vaccine. Usually other types of tests are performed to provide this type of information. See the individual articles on Hepatitis A, B or C for more on this.
Are these tests always run as a panel?
No. Sometimes if it is known the particular hepatitis virus a person was exposed to, then tests specific for that virus may be performed. Also, some of these tests are used for other purposes, such as monitoring the progression of disease or determining if treatment is working, and they may be run singly or in different combinations in those cases. For more about other tests used in viral hepatitis infections, see the individual articles on Hepatitis A, Hepatitis B, and Hepatitis C.
What other laboratory tests might my doctor perform?
If I have viral hepatitis, am I contagious?
You may be contagious. It depends on which hepatitis virus you were infected with and the stage of your infection. Often, people with viral hepatitis can spread the infection even though they don't have symptoms. With Hepatitis A, you are contagious from about 2 weeks after you are infected until about 1 weekafter the onset of symptoms. A person with Hepatitis B is contagious as long as the virus is present in their blood. Anyone who tests positive for the presence of Hepatitis C virus (HCV RNA test) should be considered contagious. The HCV RNA test may be performed as follow up to a positive result for anti-HCV.
The results for my hepatitis tests came back negative. What other conditions can cause similar symptoms?
Hepatitis can be caused by several different factors and conditions such as alcohol, drugs like acetaminophen, or inherited disorders. (For more on these, see the article on Hepatitis.) There are a few other viral infections that may cause similar symptoms, such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV). An autoimmune disease is another possibility your doctor may need to consider if your hepatitis tests are negative.