Objective: Data on fecal calprotectin and S100A12 in predicting wireless capsule endoscopy (WCE) findings in suspicion of Crohn's disease (CD) are scarce. Our aim was to study the role of calprotectin and S100A12 in predicting inflammatory lesions of small bowel in patients undergoing WCE.
Material and methods: 84 patients undergoing WCE (77 for suspicion of CD and 7 CD patients for evaluation of disease extent) were prospectively recruited. WCE findings were scored. Patients provided a stool sample for measurements of biomarkers. Patients underwent an esophagogastroduodenoscopy and ileocolonoscopy before WCE.
Results: WCE was abnormal in 35 (42%) of 84 patients: 14 patients with CD, 8 with NSAID enteropathies, 8 with angioectasias, 4 with polyps or tumors, and 1 with ischemic stricture. Median calprotectin concentration in the study population was 22 μg/g (range 2-342) and S100A12 concentration 0.048 μg/g (range 0.003-1.215). Fecal calprotectin was significantly higher in CD patients (median 91, range 2-312) compared with those with normal WCE or other abnormalities (p = 0.008), whereas fecal S100A12 (0.087 μg/g, range 0.008-0.896) did not differ between the groups (p = 0.166). In detecting inflammatory small bowel lesions, sensitivity, specificity, positive predictive value, and negative predictive value for fecal calprotectin (cutoff 50 μg/g) were 59%, 71%, 42%, and 83%, and for S100A12 (cutoff 0.06 μg/g) these were 59%, 66%, 38%, and 82%.
Conclusions: In predicting small bowel inflammatory changes, fecal biomarkers calprotectin and S100A12 have moderate specificity, but low sensitivity. Neither fecal calprotectin nor S100A12 can be used for screening or excluding small bowel CD.