Is faecal calprotectin equally useful in all Crohn's disease locations? A prospective, comparative study

INTRODUCTION There are data suggesting that the diagnostic usefulness of faecal calprotectin (FC) may vary depending on the Crohn's disease (CD) location. The aim of the study was to compare the diagnostic usefulness of FC in CD patients with different disease locations. MATERIAL AND METHODS We prospectively enrolled 120 CD patients in the study. Disease activity was assessed by using Crohn's Disease Activity Index (CDAI), biochemical markers, and endoscopic and radiographic methods. Faecal calprotectin concentration was assessed in single stool samples by using the ELISA method. RESULTS Among all patients, 54 (45%) had ileocolonic CD location, 44 (36.5%) had isolated small bowel location, and 22 (18.5%) had colonic CD location. FC correlated significantly with C-reactive protein concentration and endoscopic and radiographic activity among patients with isolated small bowel CD (p = 0.03, r = 0.32; p < 0.0001, r = 0.78; p = 0.03, r = 0.35; respectively) and with C-reactive protein and endoscopic activity in isolated colonic CD (p = 0.0009, r = 0.7; p = 0.0002, r = 0.78; respectively). CDAI and inflammatory biochemical markers did not correlate with endoscopic and radiographic assessment in small bowel CD. In patients with ileocolonic CD, FC correlated significantly with endoscopy (p = 0.006, r = 0.5), radiographic assessment (p = 0.04, r = 0.3), CDAI (p = 0.0006, r = 0.5) and the majority of biochemical markers. CONCLUSIONS Faecal calprotectin is a useful diagnostic marker in all CD patients. Although its usefulness in small bowel CD seems to be the lowest, it should be utilized particularly in this disease location because of the lack of other reliable, non-invasive diagnostic methods.