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Secretory IgA
Doctor's Data1 test optionFrom $207.90
Secretory IgA
Doctor's DataCatalog information reviewed: August 24, 2026 by the Sunridge Medical clinical team.
What this laboratory test evaluates
The GI tract serves a vital function by excluding the uptake of enteropathogens, which is accomplished in large part by the antigen binding activity of the immunoglobulin secretory IgA. 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. As the principal immunoglobulin isotype present in mucosal secretions, sIgA plays an important role in controlling intestinal milieu which is constantly presented with potentially harmful antigens such as pathogenic bacteria, parasites, yeast, viruses, abnormal cell antigens, and allergenic proteins. Fecal secretory IgA antibodies exert their function by binding to antigenic epitopes on the invading microorganism, limiting their mobility and adhesion to the epithelium of the mucus membrane. This prevents the antigens from reaching systemic circulation and allowing them to be excreted directly in the feces.
Additional test information
The lining of the gastrointestinal (GI) tract acts as an essential protective barrier, housing a primary part of the body's immune response. Secretory IgA (sIgA) – a type of antibody produced in mucosal areas of the body, including the gastrointestinal tract – stands out as the principal antibody in this context acting as the frontline defense within the gastrointestinal mucosa by aiding in the prevention of pathogen absorption. Assessing fecal sIgA levels through this laboratory stool testing offers practitioners valuable insights into a patient's intestinal immune function and capacity to counteract detrimental antigens.
Collection and processing
- Sample type: Stool
- Fasting: No
- Estimated laboratory processing: Results should arrive 4 to 6 days after the lab receives samples.
How Sunridge uses laboratory information
Sunridge considers the medical question, symptoms, history, medications, prior results, and whether the finding could change care before recommending testing. A laboratory result is not interpreted in isolation and does not establish a diagnosis by itself.
Before requesting this test
Availability, collection requirements, eligibility, and processing estimates can change. Sunridge reviews each request and, when appropriate, creates the order through Fullscript. Follow the current instructions supplied with the approved order.
Related Sunridge care
Learn how Sunridge approaches Digestive Conditions and ask whether this test is appropriate for your clinical question.
Common questions about this laboratory test
- What sample does this test require?
- The listed sample type is Stool. Confirm current collection instructions in the approved order.
- Does this test require fasting?
- The current catalog record lists fasting as: No. Follow the instructions supplied with the approved order.
- How long does laboratory processing usually take?
- Results should arrive 4 to 6 days after the lab receives samples.. Timing can change after collection or if a laboratory requires additional review.
About this test
The GI tract serves a vital function by excluding the uptake of enteropathogens, which is accomplished in large part by the antigen binding activity of the immunoglobulin secretory IgA. 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. As the principal immunoglobulin isotype present in mucosal secretions, sIgA plays an important role in controlling intestinal milieu which is constantly presented with potentially harmful antigens such as pathogenic bacteria, parasites, yeast, viruses, abnormal cell antigens, and allergenic proteins. Fecal secretory IgA antibodies exert their function by binding to antigenic epitopes on the invading microorganism, limiting their mobility and adhesion to the epithelium of the mucus membrane. This prevents the antigens from reaching systemic circulation and allowing them to be excreted directly in the feces.
Additional details
The lining of the gastrointestinal (GI) tract acts as an essential protective barrier, housing a primary part of the body's immune response. Secretory IgA (sIgA) - a type of antibody produced in mucosal areas of the body, including the gastrointestinal tract - stands out as the principal antibody in this context acting as the frontline defense within the gastrointestinal mucosa by aiding in the prevention of pathogen absorption. Assessing fecal sIgA levels through this laboratory stool testing offers practitioners valuable insights into a patient's intestinal immune function and capacity to counteract detrimental antigens.
Highlighted health areas
- Immune System
- Gastrointestinal
Biomarkers and report focus
The exact analytes and report format can change. Confirm the current contents in the Fullscript order before payment.
- Secretory IgA