Secretory IgA (sIgA)
Secretory IgA (sIgA) is the main antibody guarding mucosal surfaces, and its level in stool reflects the tone of the gut immune system. A preventive practice tracks it because low values can indicate mucosal immune suppression while high values suggest an active immune challenge.
What It Measures
Mucosal antibody reflecting gut immune tone.
Optimal vs. Lab Range
Target range for optimal health and longevity based on research.
Population-based reference range from standard labs.
Why It Matters
Low = immunosuppression; high = active mucosal challenge.
When Low
Low → immune exhaustion, chronic stress.
When Optimal
Mid-range → balanced mucosal defense.
When High
Elevated → active infection/antigen exposure.
How to Optimize
Manage chronic stress, sleep, colostrum, S. boulardii, vitamin A repletion.
Key Interventions & Linked Compounds
Moderate (6/10)Key Interventions
Linked Compounds & Supplements
Curated from clinical literature. Individual results vary; consult a qualified clinician before changing a protocol.
Ordering Notes
Specimen
Serum or plasma (venous draw)
Patient prep
No fasting required. Maintain usual diet and medications unless advised.
Recommended cadence
Re-test every 3–6 months when actively optimizing; annually for monitoring.
Reporting unit
mg/dL stool
Pre-analytic notes
Standardize draw time of day, hydration, and recent exercise. Note any acute illness, supplements, or hormonal therapies on the requisition.
Recommended Follow-Up Actions
- 1
Confirm the result is reliable
Repeat abnormal values before acting — preferably from the same lab, same time of day, and under consistent prep. Rule out acute illness, recent intense exercise, or medication effects that can shift Secretory IgA (sIgA).
- 2
Compare against optimal, not just lab range
Use the optimal window above as the target. Lab "normal" is built from the general population and often misses early dysfunction.
- 3
Pair with related markers
Order a complementary panel covering metabolic, inflammatory, and hormonal context to interpret this marker properly.
- 4
Discuss interventions with a clinician
Use the interpretation guidance above to frame the conversation. Bring trends, not just one datapoint, to your visit.
- 5
Re-test on a defined cadence
If a change is implemented, re-measure in 8–12 weeks for fast-moving markers, or 3–6 months for slower ones, to confirm response before escalating.
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