Back to tests and procedures
Haemophilus influenzae Antibody
Does this test have other names?
Haemophilus influenzae type b (Hib) IgG antibody level
What is this test?
This test measures the amount of anti-Hib IgG immunoglobulin, or antibody, in your blood.
There are many types of Haemophilus influenza bacteria. They can live in your mouth, throat, ears, and airways and don't always cause illness. H. influenza type b (Hib) one of the most serious types. It doesn't cause the flu, although it has a similar-sounding name. It causes bacterial meningitis. Hib also causes ear and sinus infections and can worsen chronic obstructive pulmonary disease, or COPD. It also causes some types of pneumonia.
In general, Hib infection is passed through coughing, sneezing, or contact with infected body fluids.
Before 1990, Hib was the leading cause of bacterial meningitis in children younger than 5. The Hib vaccine is now routinely given to children to prevent infection.
This test can find out whether your body has responded to the Hib vaccine. It's usually done if your immune system isn't working the way it should.
Why do I need this test?
You may need this test if your doctor isn't sure whether you have developed immunity against Hib after getting the vaccine. You may also get this test both before and a few weeks after a dose of Hib vaccine to measure changes in the amount of Hib antibodies your body is able to make.
What other tests might I have along with this test?
Your doctor may also order other tests, including:
Complete blood count, or CBC
Immunoglobulin levels, or IgG, IgA, and IgM
Other specific antibody levels, such as antibodies against Streptococcus pneumoniae
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your health care provider.
A positive result means that antibodies were found in your blood. That means that you are or were recently infected with Hib or that your immune system was able to respond well to the Hib vaccine. Your doctor will make a final diagnosis based on a physical exam, your symptoms, and other test results.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
If you have other bacteria in your blood, you may have a false-positive on this test. These bacteria include E. coli and S. pneumonia.
How do I get ready for this test?
You don't need to prepare for this test. But be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.