About the Test
Purpose of the test
The purpose of hepatitis A testing is to determine if a person has been infected by the hepatitis A virus (HAV).
The hepatitis A virus is highly contagious, and infection can cause hepatitis, a condition characterized by inflammation and enlargement of the liver. There are several viruses that can cause hepatitis. Some hepatitis viruses cause only short-term infections called acute disease, while others can cause long-term infections known as chronic disease.
Hepatitis A is typically a sudden, acute infection that lasts a few weeks to several months. In most cases, this virus does not cause chronic infection. In rare cases, though, Hepatitis A can be severe and cause liver damage or liver failure.
This virus is spread through fecal-oral transmission, which means that a person contracts the disease when they ingest traces of the feces, also called stool, of a person infected with hepatitis A. Most often, transmission of hepatitis A occurs through consuming unwashed food or water that has been contaminated.
A doctor may order hepatitis A testing for several purposes:
- Diagnose current infection: Doctors use hepatitis tests to diagnose the cause of hepatitis in patients with signs and symptoms of this disease.
- Assess immunity: After a person recovers from a hepatitis A infection, they become immune to future infections due to the development of protective antibodies. Hepatitis A testing may show that a person has developed protective antibodies to hepatitis A after recovering from a past infection or because they previously received a hepatitis A vaccination.
What does the test measure?
To determine if viral hepatitis is caused by the hepatitis A virus, hepatitis A testing looks for certain antibodies. Antibodies are substances made by the immune system in response to infection with a virus such as hepatitis A.
Hepatitis A testing looks for two types of antibodies. Antibodies are part of the body’s protective response to a viral infection, and hepatitis A virus antibodies may be measured by a few different tests:
- Hepatitis A immunoglobulin M (IgM anti-HAV) antibody test: When a person is first infected with hepatitis A, the body produces IgM anti-HAV antibodies. These antibodies are usually detectable from two weeks after symptoms begin to around six months later.
- Hepatitis A immunoglobulin G (IgG anti-HAV) antibody test: The IgG anti-HAV antibody test detects IgG antibodies that develop later in the course of the disease. IgG antibodies are detectable in the body for life, providing protection against a future hepatitis A virus infection. The IgG anti-HAV test is used to detect past HAV infections and may occasionally be used to determine if an individual has developed immunity from a previous infection or vaccination.
- Total hepatitis A antibody test: The total HAV antibody test detects both IgM and IgG antibodies and thus is used to identify both current and past infections.
Although testing the blood for HAV antibodies is the gold standard for identifying a hepatitis A infection, other tests may be ordered that instead look for the genetic material of the hepatitis A virus. This type of testing, also called nucleic acid amplification testing (NAAT), can detect traces of hepatitis A in a patient’s stool, blood, body fluids, and liver tissue.
In many cases, specific hepatitis A testing occurs along with or after blood tests that measure liver function. These tests may include a broad panel of tests, called a liver panel. The measurements in a liver panel can provide information about liver function and inflammation. While these tests can suggest viral hepatitis, they cannot identify the specific virus, which is why antibody testing may be prescribed to confirm the underlying cause.
When should I get hepatitis A testing?
Doctors often recommend testing for hepatitis based on a patient’s medical history, symptoms, and a physical exam.
Most adults with hepatitis A have symptoms that develop around 28 days after infection. Children under six years old rarely have symptoms. Symptoms of hepatitis A include:
- Dark urine
- Diarrhea and stool that is gray- or clay-colored
- Low-grade fever
- Abdominal or joint pain
- Nausea, vomiting, or loss of appetite
- Yellow eyes and skin, also called jaundice
Doctors may recommend hepatitis A testing in patients with symptoms and a known exposure to HAV or an elevated risk of contracting this disease. Factors that increase the risk of exposure to hepatitis A include:
- Travel, especially to Asia, South America, Central America, Africa, and the Middle East
- Using intravenous drugs and the use of illegal drugs
- Living in a nursing home
- Working in industries involving health care, food, or sewage
- Eating raw shellfish, vegetables, and other foods
In patients who develop symptoms of hepatitis A without a known exposure to the virus, doctors may recommend an acute viral hepatitis panel that looks for hepatitis A, hepatitis B, and hepatitis C in the same blood sample.
Finding Hepatitis A Testing
How to get tested
Hepatitis A testing uses a sample of blood to test for antibodies against the hepatitis A virus. When prescribed by a doctor, a blood sample may be collected in a hospital or other medical setting and sent to a laboratory for analysis.
Blood is usually drawn from a vein in the patient’s arm or the back of the hand.
Can I take the test at home?
At-home testing for hepatitis A is not currently available in the United States. Hepatitis A testing requires blood to be drawn by a health care professional in a hospital, laboratory, or other medical setting.
How much does the test cost?
When ordered by a doctor, testing for hepatitis A may be paid for by a patient’s health insurance coverage. Health plans vary, so it’s important for patients with health insurance to talk to an administrator about the cost of testing, including any copays or deductibles that may be required.
If a patient doesn’t have health insurance coverage that covers hepatitis A testing, it may be helpful to discuss the cost of testing with a doctor. The total cost can include the office visit, the blood draw, and technician fees in addition to the cost of laboratory testing.
Taking a Hepatitis A Test
Hepatitis A testing is performed on a sample of blood. To obtain the sample, a doctor, nurse, or other health care provider uses a small needle to draw blood from a vein.
Before the test
Generally, patients do not need to prepare for hepatitis A testing. As with other blood tests, patients should talk to their doctor about any prescription or over-the-counter drugs they are taking, but it is rare to have to adjust medications before a hepatitis A test.
During the test
Hepatitis A testing is conducted on a sample of blood that can be collected through a blood draw or by puncturing the skin.
During a blood draw, a health care provider takes a sample of blood from a vein in the patient’s arm. After locating an appropriate vein and cleaning the collection site, a small needle is inserted into the vein, and blood is collected in an attached vial. A blood draw usually takes less than five minutes.
When testing for hepatitis A in infants and young children, a device with a very small needle called a lancet may be used to puncture the skin to collect blood. Once the skin is punctured, a small amount of blood is collected in a tube or vial.
After the test
After a blood sample is collected, a bandage or piece of gauze may be applied to reduce additional bleeding. Risks of blood collection are minimal, although patients may have light bruising and tenderness where the needle was inserted. There are no restrictions on normal activities after a blood sample is collected.
Hepatitis A Test Results
Receiving test results
Hepatitis A test results may be available within a few business days after the laboratory receives the blood sample. Patients may receive test results during a follow-up appointment or through an electronic medical record. Results may also be given by phone or postal mail.
Interpreting test results
Hepatitis A test results may include the results of anti-HAV IgM antibody testing, anti-HAV IgG antibody testing, or the sum of both antibodies in total antibody testing.
A negative test result on an anti-HAV IgM antibody test indicates that IgM antibodies were not found in the test sample and that the patient does not have a current hepatitis A infection. If an anti-HAV IgG antibody test or total antibody test was performed and results are also negative, a person does not currently have hepatitis A and shows no evidence of immunity from either vaccination or a past infection.
If hepatitis A testing detects anti-HAV IgM or IgG antibodies, the interpretation of the test depends on the specific results. The table below outlines potential interpretations of positive test results:
|Hepatitis A Test Results
|IgM Anti-HAV Antibody Test
|IgG Anti-HAV Antibody Test or Total Antibody Test
|Acute or recent hepatitis A infection
|No active infection but has developed immunity to HAV
|Has been exposed to HAV but acute infection cannot be ruled out. May have immunity.
|No current or previous HAV infection. Not immune.
Are test results accurate?
While no blood test is accurate all of the time, hepatitis A testing is the standard and accepted method of determining whether or not a person has an active hepatitis A infection or formed immunity.
Although a positive result on an IgM anti-HAV antibody test is considered diagnostic for an acute infection with hepatitis A, this result may be less helpful in patients who aren’t experiencing symptoms of hepatitis. In patients without symptoms, finding IgM anti-HAV antibodies may reflect a prior hepatitis A infection in which IgM antibodies have remained in the body for longer than usual or an asymptomatic infection.
Do I need follow-up tests?
The need for follow-up tests depends on the results of hepatitis A testing. When symptoms are significant, testing may be used to monitor a patient’s liver function, assess appropriate nutrition, and manage any complications of the disease.
If a patient tests negative for a hepatitis A infection and doesn’t already have immunity, their doctor may suggest hepatitis A vaccination. Vaccination is highly effective at preventing this infection. Vaccination is recommended by the Centers for Disease Control and Prevention (CDC) for all children aged 12-23 months, children and young adults aged 2 to 18 who weren’t vaccinated as infants, pregnant women at risk for hepatitis A, and anyone who requests vaccination.
Questions for your doctor about test results
For support in understanding the results of hepatitis A testing, patients should discuss results with their doctor. Questions about test results may include:
- What is my test result?
- Do I have a hepatitis A infection?
- Does the test result suggest that I have immunity to the hepatitis A virus?
- Would I benefit from hepatitis A vaccination?
- Do I need any follow-up tests based on my hepatitis A test results?