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.