Assessing endoscopic remission in small bowel Crohn's disease: Are markers enough?

Table 1 Biomarkers and their attributes in inflammatory bowel disease

	Marker	Advantages	Limitations
Conventional markers	CRP	Readily available. Cheap. Sensitive for inflammation	Not disease specific. More sensitive for CD than UC. Lower sensitivity for small bowel disease
	ESR	Readily available. Cheap. Sensitive for inflammation	Not disease specific. Elevated in non-inflammatory conditions. More relevant for subacute than acute
	FCP	Readily available. Cheap Sensitive for gut inflammation. Can be used to monitor treatment response	Not specific for IBD. Influenced by external factors (exercise…). Lower sensitivity for small bowel disease
	FIT	Readily available. Cheap. Fair sensitivity for gut inflammation	Low specificity for IBD. Low accuracy for small bowel disease
	LRG	Independent of IL-6. More sensitive for intestinal inflammation than CRP. Acceptable correlation with small bowel disease	Not very cheap. Limited availability
Novel markers	OM	Correlates with inflammation. Can be useful in IBD	Not readily available yet. Not studied for small bowel disease
	FM	Correlates with inflammation. Can be useful in IBD	Not readily available yet. More useful in UC than CD. Not studied for small bowel disease
	F mRNA	Correlates with inflammation. Can be useful in IBD	Expensive. Not tested for small bowel disease
	BAF	Can be useful in IBD. Available data in both UC and CD. Potential role in treatment	Expensive. Not tested for small bowel disease. Not specific to IBD

CRP: C-Reactive protein; ESR: Erythrocyte sedimentation rate; FCP: Fecal calprotectin; FIT: Fecal immunohistochemical test; LRG: Leucine-rich α2 glycoprotein; OM: Oncosttatin M; FM: Fecal myeloperoxidase; Fm RNA: Fecal microRNA; BAF: B-cell activating factor; IBD: Inflammatory bowel disease: UC: Ulcerative colitis; CD: Crohn’s disease; IL-6: Interleukin 6.