What is the reference range for Secretory Immunoglobulin A?

The standard reference range for Secretory Immunoglobulin A is Laboratory-specific; typical range approximately 500–2,000 µg/g stool.. Reference ranges vary by laboratory and assay platform — interpret in context of the issuing laboratory's stated range.

Which tests measure Secretory Immunoglobulin A?

Secretory Immunoglobulin A is measured in 1 test on BiomarkersLabs.com, including Add-On: Fecal SIgA.

Biomarker Reference · SIgA

What does the Secretory Immunoglobulin A test measure?

Secretory Immunoglobulin A (SIgA) is a clinical biomarker used in microbiome-gut assessment. Secretory IgA is the predominant antibody class in mucosal secretions and the primary humoral defence at the intestinal epithelium. It is measured in 1 laboratory test on BiomarkersLabs.com.

Reference Range: Laboratory-specific; typical range approximately 500–2,000 µg/g stool.
Units: mg/g stool, µg/g stool
Measured In: 1 test
Category: —

Functional medicine optimalFunctional practitioners often interpret values in the mid-to-upper reference range as optimal, though this is not supported by outcomes-based evidence.

What is Secretory Immunoglobulin A?

Secretory IgA is the predominant antibody class in mucosal secretions and the primary humoral defence at the intestinal epithelium. It is produced by plasma cells in the lamina propria, transported across the epithelium bound to the polymeric immunoglobulin receptor, and released into the lumen as a dimeric molecule with a secretory component. SIgA binds and neutralises pathogens, toxins, and dietary antigens, blocks microbial adherence, and modulates the commensal microbiota without triggering inflammation. Faecal SIgA concentration reflects the functional output of the gut-associated lymphoid tissue and the mucosal barrier's immunological tone.

Why is Secretory Immunoglobulin A measured?

Fecal SIgA is used in functional and integrative gastroenterology as a marker of mucosal immune competence and intestinal barrier integrity. Low concentrations are interpreted as impaired mucosal defence, which may correlate with dysbiosis, chronic infection, or immune exhaustion, though the threshold for clinically significant suppression is not standardised. Elevated SIgA may reflect an active mucosal immune response to pathogens, inflammation, or antigenic challenge. Because the marker is method-dependent and interpretive thresholds are not universally defined, results are used to inform a functional assessment rather than to diagnose or exclude specific disease.

Reference ranges

Standard reference: Laboratory-specific; typical range approximately 500–2,000 µg/g stool.
Functional medicine optimal: Functional practitioners often interpret values in the mid-to-upper reference range as optimal, though this is not supported by outcomes-based evidence.
Units: mg/g stool, µg/g stool

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.

Tests that measure Secretory Immunoglobulin A

1 test on BiomarkersLabs.com include this biomarker.

BML-MBG-004Comprehensive

Add-On: Fecal SIgA

Secretory Immunoglobulin A reference range in this test: Laboratory-specific; typical range approximately 500–2,000 µg/g stool.

Related clinical conditions

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