Fecal calprotectin as a biomarker of inflammatory lesions of the small bowel seen by videocapsule endoscopy.

INTRODUCTION: The levels of calprotectin in the stools are proportional to neutrophil activity in the enteric lumen, so fecal calprotectin is a useful intestinal inflammatory biomarker. It is an extended tool as predictor of colonic pathology but there is scare evidence about its utility in the small bowel.

OBJECTIVE: To test the yield of fecal calprotectin to detect lesions in the small bowel.

MATERIAL AND METHODS: We have retrospectively included 71 patients sent for small bowel capsule endoscopy in study for suspected inflammatory bowel disease. All of them had a determination of fecal calprotectin and had been sent to colonoscopy with no findings. Patients have been divided in groups: A, fecal calprotectin < 50 microg/g; B, fecal calprotectin: 50-100 microg/g; C, fecal calprotectin > 100 microg/g, and we have analyzed which of them presented inflammatory lesions in capsule endoscopy studies.

RESULTS: The rate of patients with signi ficative lesions was 1 out of 10 (10%) in group A, 6 out of 24 (25%) in group B, and 21 out of 34 (62%) in group C. If we consider levels over 50 ìg/g pathologic, fecal calprotectin presents sensitivity: 96%, specificity: 23%, NPV: 90% and PPV: 56%. If we consider levels over 100 ìg/g pathologic these values are sensitivity: 75%, specificity: 67%, NPV: 79% and PPV: 62%.

CONCLUSIONS: Fecal calprotectin has high sensitivity but not so good specificity for predicting small bowel lesions after a normal colonoscopy. In daily practice it will be more useful to establish in 100 ìg/g the limit to indicate capsule endoscopy studies.