Tests and diagnosis

By Mayo Clinic Staff

To help decide whether recurrent infections could be due to primary immunodeficiency, your doctor will begin by asking a number of questions, such as what health problems you have, how long infections last, how severe they are and whether they respond to treatment. Your doctor will also want to know whether any close relatives have an inherited immune system disorder. Your doctor will perform a physical examination to look for clues that may indicate the cause of your illness.

There are several tests used to diagnose an immune disorder. They include:

  • Blood tests. In most cases, blood tests can reveal abnormalities in the immune system that indicate an immune deficiency disorder. Tests can determine if you have normal levels of infection-fighting proteins (immunoglobulin) in your blood. Tests can measure the levels of different blood cells and immune system cells. Abnormal numbers of certain cells can indicate an immune system defect. Other blood tests can determine if your immune system is responding properly and producing antibodies — proteins that identify and kill foreign invaders such as bacteria or viruses.
  • Identifying infections. If you have an infection that's not responding to standard treatment, your doctor may do tests to try to identify exactly what germs are causing it.
  • Prenatal testing. Parents who've already had a child with a primary immunodeficiency disorder may want to have testing done for certain immunodeficiency disorders during future pregnancies. Samples of the amniotic fluid, blood or cells from the tissue that will become the placenta (chorion) are tested for abnormalities. In some cases, DNA testing is done to test for a genetic defect. Test results make it possible to prepare for treatment soon after birth, if necessary.
Jul. 30, 2013

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