Synonyms: Immunoglobulin A
Related tests: serum electrophoresis, urine electrophoresis, kappa light chains, lambda light chains, IgG, IgM
Clinical significance
Class A immunoglobulins are the antibodies that normally predominate in secretions (e.g. breast milk), acting on the mucous membranes. In white people, 1 in 700 has an isolated genetic IgA deficiency, and it should also be remembered that very young children (under 5) may not yet produce significant amounts of IgA.
About 10-15% of myelomas are IgA myelomas.
Clinical indications
Further investigation when a monoclonal component is found on electrophoresis; screening for IgA deficiency before testing for IgA anti-gliadin and anti-transglutaminase antibodies; recurrent infections of the lower airways and gut.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed. You must have been standing or sitting upright for at least 30 minutes.