An IgA test determines the amount of immunoglobulin A in your blood, which is one of the most frequent forms of antibodies in the body. Antibodies (also known as immunoglobulins) are proteins produced by the immune system to identify and eliminate pathogens. High IgA levels are normally seen in the mucous membranes of the body, particularly in the respiratory and gastrointestinal tracts, as well as in saliva (spit) and tears.
