blood immunoglobulin A amount EFO:0004912 EFO:0801091 Trait.ontology MP:0002495 IgA concentration VT:0001807 plasma immuglobulin A amount IgA level The proportion, quantity, or volume in whole blood, serum, or plasma of the principal immunoglobulin in exocrine secretions; prevents pathogens from invading the body through the mucosa of the gastrointestinal, pulmonary, and genitourinary tracts. blood immunoglobulin amount