Health Library

Quantitative Immunoglobulins

Does this test have other names?

IgA, IgE, IgG, IgM; immunology testing

What is this test?

This test measures the amount of antibodies called immunoglobulins in your blood.

Your immune system makes antibodies to fight off bacteria, viruses, and other invaders that could harm your health. Your body makes several types of immunoglobulin antibodies: M, G, A, and E. They are called IgM, IgG, IgA, and IgE. IgG is found in your blood and tissue. IgM is mostly found in your blood. IgA is found at high levels in fluid your mucus membranes make, such as saliva, tears, and nasal secretions. IgE is mostly attached to cells in your immune system.

Some people have deficiencies in one or more of these immunoglobulins, which puts them at risk for infections.

Why do I need this test?

You may need this test if your doctor suspects that you have a immunoglobulin deficiency. Symptoms of a deficiency in IgG, IgA, or IgM include frequent or severe infections such as:

  • Sinusitis

  • Pneumonia

  • Ear infections

  • Viral lung infections

What other tests might I have along with this test?

Your doctor may recommend other tests, such as:

  • Complete blood count, including measuring the amount of certain cells in your blood

  • Measurement of different proteins in your blood

  • Urinalysis to check for kidney problems

  • Check for other conditions that can affect your immune system, such as kidney disease and diabetes

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.

Results may show low levels of one or more immunoglobulins. Depending on the specific kind, it may mean you have one of these problems:

  • Common variable immunodeficiency. This is a condition that causes the immune system to work poorly. It often shows up in young adults but may be diagnosed in children. It's marked by low IgG levels.

  • Ataxia telangiectasia. This is a serious disease of immunodeficiency. It tends to be disabling and fatal by the late teenage years.

  • Multiple myeloma and certain types of leukemia, which are types of cancer

  • Certain autoimmune diseases, such as lupus, rheumatoid arthritis, and Hashimoto's thyroiditis

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?

No other factors can affect your test results.

How do I get ready for this test?

You don't need to prepare for this test.  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.