blood immunoglobulin measurement blood immunoglobulin A level 2014-01-27T12:19:02Z CMO:0002094 JSmith The amount in a specified sample of blood of one or more types of immunoglobulin A (IgA), one of the most prevalent of the five classes of antibodies produced by the body. IgA is found in all secretions of the body and is the major antibody in the tears, saliva, and mucous membranes lining the intestines and bronchi, constituting an important factor in mucosal immunity. blood IgA level clinical_measurement_ontology