The usefulness of fecal calprotectin in assessing inflammatory bowel disease activity

Background: Mucosal healing is reported to be associated with sustained remission and reduced risk of surgery in inflammatory bowel disease (IBD). Fecal calprotectin (FC) is known to correlate with disease activity and can be used as a predictor for relapse or treatment response in IBD. We aimed to assess the usefulness of the FC as a marker of disease activity and mucosal healing (MH) in patients with IBD. In addition, we compared a quantitative rapid) with established ELISA method. Methods: Seventy nine test (Quantum Blue patients with IBD were enrolled, of which 49 were Ulcerative colitis (UC) and 30 were Crohn`s disease (CD). FC levels were analyzed by both ELISA and quantitative rapid test. Patients` medical records were reviewed for clinical, laboratory and endoscopic data. In UC, MH was defined as a Mayo endoscopic g/g in UC and was subscore of 0. Results: The mean FC level was 998.1±1610.1 g/g in CD, respectively. There was a strong correlation between 1167.3±1317.3 FC level and clinical activity indices (Mayo score and CDAI) (p<0.001). FC levels showed good correlations with WBC count and C-reactive protein levels. There were no differences in FC levels according to disease location and extension both in UC and CD. FC level was significantly lower in patients with g/g, MH compared to those without MH in UC (81.0±59.5 vs. 1039.7±1598.1, p=0.021). The results from a quantitative rapid test corresponded well to those from ELISA. Conclusions: FC test is a simple and useful method for investigating IBD activity. In particular, FC is a good surrogate marker for MH. The quantitative rapid test, which is more rapid and easier to use, can be used as a reliable alternative to the time consuming ELISA. Thus, FC has the potential to replace colonoscopy for assessment of mucosal inflammation in clinical practice.