IgA accounts for 13% of the plasma immunoglobulins and serves to protect the skin and mucosa against microorganisms. It is capable of binding toxins, and develops in combination with lysozyme antibacterial and antiviral activity. IgA is the predominant immunoglobulin in bodily secretions such as colostrum’s, saliva, and sweat. Secretory IgA provides defence against local infections and is important in binding food antigens in the gut. In serum, IgA exists in monomeric, dimeric and trimeric forms, where as in bodily secretions it exists in dimeric form with an additional chain.

Biorex Diagnostics manufactures IgA reagents designed for Hitachi 917, Olympus AU600/400/640/2700 and CA 180/280/400 Furuno/Daytona systems.