Immunoglobulin test

A test for immunoglobulins (antibodies) in the blood is done to:

• Find certain autoimmune diseases or allergies.
• Find certain types of cancer (such as multiple myeloma or macroglobulinemia).
• See whether recurring infections are caused by a low level of immunoglobulins.
• Check the treatment for certain types of cancer affecting the bone marrow.
• 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 may be done when the results of a blood protein electrophoresis or total blood protein test are abnormal.

A health professional uses a needle to take a blood sample, usually from the arm.

In general, there’s nothing you have to do before this test, unless your doctor tells you to.

Normal

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

High values

• IgA. High levels of IgA may mean that multiple myeloma is present. Levels of IgA also get higher in some autoimmune diseases, such as rheumatoid arthritis, and in liver diseases, such as cirrhosis.
• IgG. High levels of IgG may mean a long-term (chronic) infection, such as tuberculosis, is present. Levels of IgG also get higher in IgG multiple myeloma, long-term liver disease, and systemic lupus erythematosus (SLE). In multiple myeloma, tumor cells make only one type of IgG antibody (monoclonal); the other conditions cause an increase in many types of IgG antibodies (polyclonal).
• IgM. High levels of IgM can mean macroglobulinemia, viral hepatitis, mononucleosis, rheumatoid arthritis, or a bacterial infection is present. Because IgM antibodies are the type that form when an infection occurs for the first time, high levels of IgM can mean a new infection is present. High levels of IgM in a newborn mean that the baby has an infection that started in the uterus before delivery.
• IgD. How IgD works in the immune system is not clear. A high level may mean IgD multiple myeloma is present. IgD multiple myeloma is much less common than IgA or IgG multiple myeloma.
• IgE. A high level of IgE can mean a parasite infection is present. Also, high levels of IgE often are found in people who have allergic reactions, asthma, atopic dermatitis, and some types of cancer. In rare cases, a high level of IgE may mean IgE myeloma.

Low values

• IgA. Some people are born with low or absent levels of IgA antibodies. Low levels of IgA occur in some types of leukemia, kidney damage (nephrotic syndrome), a problem with the intestines (enteropathy), and a rare inherited disease that affects muscle coordination (ataxia-telangiectasia). A low level of IgA increases the chance of developing an autoimmune disease.
• IgG. Low levels of IgG occur in macroglobulinemia. In this disease, the high levels of IgM antibodies stop the growth of cells that make IgG. Other conditions that can cause low levels of IgG include some types of leukemia and a type of kidney damage (nephrotic syndrome). In rare cases some people are born with a lack of IgG antibodies. These people are more likely to develop infections.
• IgM. Low levels of IgM occur in multiple myeloma, some types of leukemia, and in some inherited types of immune diseases.
• IgE. Low levels of IgE can occur in a rare inherited disease that affects muscle coordination (ataxia-telangiectasia).