Diagnosis

Your doctor will ask about your history of illnesses and whether any close relatives have an inherited immune system disorder. Your doctor will also perform a physical examination.

Tests used to diagnose an immune disorder include:

• Blood tests. Blood tests can determine if you have normal levels of infection-fighting proteins (immunoglobulin) in your blood and measure the levels of blood cells and immune system cells. Abnormal numbers of certain cells can indicate an immune system defect.

  Blood tests can also determine if your immune system is responding properly and producing proteins that identify and kill foreign invaders such as bacteria or viruses (antibodies).

• Prenatal testing. Parents who have a child with a primary immunodeficiency disorder might want to be tested 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.