A person can get an IgA blood test at a doctor's office or at a hospital if a doctor needs to diagnose a problem related to the immune system. The test for immunoglobulin A is important for diagnosing certain autoimmune disorders, allergies and recurrent infections, according to KidsHealth. Immunoglobulin A are antibodies that are manufactured by the immune system to protect the body against infections caused by bacteria and other agents.
Another condition that an IgA test can be used for is the immune deficiency disorder called selective deficiency of IgA, relates the National Institute of Health. This is a genetic disorder.
The IgA blood test is performed by a technician and involves drawing blood from a vein in the arm. After the test, the results will indicate whether the levels are normal or not. The normal range for IgA antibodies is between 60 to 400 milligrams per deciliters, according to WebMD.