According to the report, the global stool secretory immunoglobulin A (SIgA) market was valued at ~US$ 27 Mn in 2019. It is projected to expand at a CAGR of ~3% from 2020 to 2030. Immunological activity in the gastrointestinal tract can be assessed using secretory immunoglobulin A (sIgA). Secretory IgA is the predominant antibody or immune protein; the body manufactures and releases in external secretions such as saliva, tears, and milk. It is also transported through the epithelial cells that line the intestines out into the lumen. Secretory IgA represents the first line of defense of the GI mucosa and is central to the normal function of the GI tract as an immune barrier.