Test Details: Immunoglobulin A (IgA) is the first line of immune defence in the resistance against infections. It is done by inhibiting bacterial and viral adhesion to epithelial cells. Also it helps in the neutralisation of bacterial toxins and virus, both extra- and intracellularly. IgA is known to eliminate pathogens or antigens via an IgA-mediated excretory pathway, where binding to IgA is followed by polyimmunoglobulin receptor-mediated transport of immune complexes.