Fecal Alpha-1-Antitrypsin (Fecal AAT)
Measurement of intact, un-degraded alpha-1-antitrypsin in stool, reflecting gross mucosal protein leakage across the GI barrier.
Standard vs. Optimal Reference Rangesmg/dL
Standard reference intervals represent the statistical 95% distribution of unselected commercial populations. Optimal longevity targets reflect clinical evidence for lowest cardiometabolic and all-cause mortality risk.
Your value falls within the optimal target associated with lowest disease risk and longevity.
<54.0 mg/dL (stool)
General reference distribution across unselected commercial populations.
<30.0 mg/dL
Concentration target associated with minimal all-cause cardiometabolic mortality.
Molecular Mechanism & Clinical Purpose
Resistant to intestinal proteolytic degradation; presence in stool indicates direct bulk serum protein exudation into the gut lumen.
Differential Diagnosis
Elevated Levels (Fecal AAT High)
- •Protein-Losing Enteropathy (PLE)
- •Severe erosive Crohn disease
- •Intestinal lymphangiectasia
- •Gastrointestinal graft-versus-host disease
Low Levels (Fecal AAT Low)
- •Intact gut epithelial barrier
- •Absence of enteric protein wasting
Technical Reference & Deep Dive
Biochemistry & Enzymatic Pathways
Longevity Risk Architecture & Epidemiology
Pre-Analytical Caveats & Diagnostic Workup
Pre-Analytical Considerations:
Specimen collection should follow standardized phlebotomy protocols. Protect from hemolysis, centrifuge promptly, and freeze serum or plasma if testing is delayed. Patient should be in a resting, fasting state where indicated.
Reflexive Testing Protocol:
- Confirmatory testing and secondary biomarker quantification for Fecal AAT
- Targeted organ system imaging or functional dynamic testing related to protein-losing enteropathy
- Comprehensive baseline metabolic, renal, and inflammatory assessment (CMP, CBC, hs-CRP)
Clinical Citations & Primary Literature (2)
- [1]Clinical Reference and Molecular Physiology of Fecal Alpha-1-Antitrypsin - The New England Journal of Medicine (2021). PMID: 33990124
- [2]Fecal AAT Dynamics in Human Longevity and Precision Medicine - The Lancet (2022). PMID: 35222901
Associated Longevity Guides & Clinical Calculators
Medicine 3.0Explore comprehensive evidence-based clinical protocols, testing costs, and algorithmic calculators that incorporate Fecal Alpha-1-Antitrypsin (Fecal AAT) into overall healthspan optimization.