Immunoglobulin A (IgA) Blood Test, Quantitative
An IgA test measures the blood level of immunoglobulin A, one of the most common antibodies in the body. Antibodies are proteins made by the immune system to fight bacteria, viruses, and toxins.
IgA is found in high concentrations in the body's mucous membranes, particularly the respiratory passages and gastrointestinal tract, as well as in saliva and tears.
IgA also plays a role in allergic reactions. IgA levels also may be high in autoimmune conditions, disorders in which the body mistakenly makes antibodies against healthy tissues.
An IgA test can help doctors diagnose problems with the immune system, intestines, and kidneys. It may be done in patients who have recurrent infections. It's also used to evaluate autoimmune conditions, such as rheumatoid arthritis, lupus, and celiac disease.
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