Faecal calprotectin as marker of intestinal inflammation
Core concept
- Calprotectin = S100A8/A9 heterodimer, ~60% of neutrophil cytosolic protein
- Neutrophils migrate into inflamed mucosa -> shed into the lumen -> stable in stool for up to 7 days at room temperature
- -> a direct, quantitative surrogate for mucosal neutrophil infiltration
- Its value is the negative predictive value, not the positive
- Low calprotectin -> organic mucosal inflammation is very unlikely -> supports IBS, avoids colonoscopy
- High calprotectin -> inflammation somewhere in the gut - but not specifically IBD
- It is a triage test in the young patient with diarrhoea, and a monitoring test in known IBD
3 more sections, plus exam facts
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