An immunoglobulins test is done to measure
the level of immunoglobulins, also known as
antibodies, in your blood.
substances made by the body's
immune system in response to bacteria, viruses,
fungus, animal dander, or cancer cells. Antibodies attach to the foreign
substances so the immune system can destroy them. See a picture of the
immune system .
Antibodies are specific to each type of foreign
substance. For example, antibodies made in response to a
tuberculosis infection attach only to tuberculosis
bacteria. Antibodies also work in allergic reactions. Occasionally, antibodies
may be made against your own tissues. This is called an
If your immune
system makes low levels of antibodies, you may have a greater chance of
developing repeated infections. You can be born with an immune system that
makes low levels of antibodies, or your system may make low levels of
antibodies in response to certain diseases, such as cancer.
five major types of antibodies are:
- IgA. IgA antibodies are found in areas of the body
such the nose, breathing passages, digestive tract, ears, eyes, and vagina. IgA
antibodies protect body surfaces that are exposed to outside foreign
substances. This type of antibody is also found in saliva, tears, and blood.
About 10% to 15% of the antibodies present in the body are IgA antibodies. A
small number of people do not make IgA antibodies.
- IgG. IgG antibodies are found in all body fluids.
They are the smallest but most common antibody (75% to 80%) of all the
antibodies in the body. IgG antibodies are very important in fighting bacterial
and viral infections. IgG antibodies are the only type of antibody that can
placenta in a pregnant woman to help protect her baby
- IgM. IgM antibodies are the largest antibody. They
are found in blood and lymph fluid and are the first type of antibody made in
response to an infection. They also cause other immune system cells to destroy
foreign substances. IgM antibodies are about 5% to 10% of all the antibodies in
- IgE. IgE antibodies are found in the lungs, skin,
and mucous membranes. They cause the body to react against foreign substances
such as pollen, fungus spores, and animal dander. They are involved in allergic
reactions to milk, some medicines, and some poisons. IgE antibody levels are
often high in people with allergies.
- IgD. IgD antibodies are found in small amounts in
the tissues that line the belly or chest. How they work is not clear.
The levels of each type of antibody can give your
doctor information about the cause of a medical problem.
Why It Is Done
A test for immunoglobulins (antibodies)
in the blood is done to:
- Find certain autoimmune diseases or
- Find certain types of cancer (such as
multiple myeloma or
- See whether recurring
infections are caused by a low level of immunoglobulins (especially
- Check the treatment for certain
types of cancer affecting the bone marrow.
- Check the treatment for
Helicobacter pylori (H. pylori)
- Check the response to immunizations to see if you are
immune to the disease.
- Check to see if you have an infection or have had it in the past.
This test is often done when the results of a blood protein
electrophoresis or total blood protein test are abnormal.