Why do I need an immunoglobulins blood test?

If you have low immunoglobulins, you have an immunodeficiency.

Symptoms of low levels of immunoglobulins usually include having many, repeated infections and other problems, such as:

• Sinus, throat, and ear infections
• Respiratory infections, such as pneumonia and bronchitis
• Diarrhea
• Serious infections from germs that don’t usually cause problems in healthy people, such as:
  • Cytomegalovirus (a virus related to chickenpox)
  • A yeast infection in the mouth, eyes, or digestive tract (thrush)

You may need an immunoglobulins test if immunodeficiency runs in your family, or your health care provider thinks you may have a problem making normal levels of immunoglobulins.

You may also need this test if your provider thinks you may have high levels of immunoglobulins from an autoimmune disease or a cancer that affects your blood, bone marrow, and/or immune system. These cancers may cause a very high level of certain immunoglobulins. But those immunoglobulins don’t work normally. So, even though your levels are high, you may have frequent infections and other symptoms of low immunoglobulin levels.

What is an immunoglobulins blood test?

This test measures the amount of immunoglobulins in your blood. Immunoglobulins are also called antibodies. Antibodies are proteins that your immune system makes to fight germs, such as viruses and bacteria. When you’re exposed to germs, your body makes unique antibodies that are specifically designed to destroy only those germs.

An immunoglobulins test usually measures three main types of immunoglobulin (Ig) antibodies that do different jobs to protect your health:

• IgM antibodies are the first immunoglobulins your body makes after you’re exposed to germs. They provide short-term protection while your body makes other antibodies. IgM antibodies are in your blood and lymph fluid (a watery fluid that carries the cells that fight infections and diseases to all parts of your body).
• IgG antibodies are very important for fighting infections from bacteria and viruses. Most of the immunoglobulins in your blood are IgG. You also have some IgG antibodies in all your body fluids. Your body keeps a “blueprint” of all the IgG antibodies you have made. That way, if you’re exposed to the same germs again, your immune system can quickly make more antibodies.
• IgA antibodies protect your respiratory tract (the organs you use to breathe) and your digestive system (the organs you use to eat and digest food) from infections. You have IgA antibodies in your blood, saliva, and gastric “juices.”

An immunoglobulins blood test measures the amounts of IgM, IgG, and IgA in your blood to help diagnose different types of health conditions that may affect your immune system.

Other names: quantitative immunoglobulins, total immunoglobulins, IgG, IgM, IgA testing

This test may be ordered along with others, such as a serum and/or urine protein electrophoresis, to help diagnose and monitor conditions associated with abnormal or excessive immunoglobulin production. When this is the case, a urine sample may be collected in addition to blood.

When is it ordered?

What is it used for?

An immunoglobulins blood test may be used to:

• Check the health of your immune system if you are often sick with infections or diarrhea
• Help diagnose and monitor a variety of conditions that may cause abnormal levels of IgM, IgG, and/or IgA, such as:
  • Autoimmune disorders. With these disorders your immune system attacks your own healthy cells by mistake, including cells that make immunoglobulins. Examples of autoimmune disorders include rheumatoid arthritis and lupus.
  • Certain types of cancer that affect your bone marrow, blood, or immune system
  • Chronic (long-term) infections
  • Genetic diseases you’re born with (uncommon)
• Check for certain infections a baby may be born with, including syphilis or toxoplasmosis