Diagnostic Value of Fecal Calprotectin in Patient with Ulcerative Colitis

BACKGROUND: Ulcerative colitis (UC) is characterized by recurrent episodes of inflammation limited to the mucosal layer of the colon. Calprotectin is a zinc and calcium binding protein derived from neutrophils and monocytes. It is easily detectable in tissue samples, body fluids, and stools, which makes it a potentially valuable marker of inflammation. The aim of the current study is to evaluate the value of fecal calprotectin (FC) as a marker of disease activity in patients with UC. METHODS: Seventy three eligible subjects underwent ileocolonoscopy and multiple biopsies were obtained from different parts of the colon and terminal ileum. All patients underwent blood and stool sampling as well as an interview to assess the disease severity utilizing ulcerative colitis activity index (UCAI), subjectively. The diagnostic value of the FC in comparison with Mayo disease activity index as the gold standard technique, was then evaluated. RESULTS: Mean FC level increased linearly according to Mayo disease activity index (r=0.44, p<0.001) and was significantly different between levels of Mayo disease activity index (p=0.003). In multivariate analysis, Mayo disease activity index, positive CRP and ESR were associated with FC level. FC level > 21.4 ng/ml was able to discriminate between active and inactive phases of UC according to Mayo disease activity index>2 with 72.3% sensitivity and 73.1% specificity. The combination of FC > 21.4 ng/ml and UCAI score of 7 had a 46.8% sensitivity and 88% specificity to diagnose Mayo disease activity index >2. Furthermore, FC level <21.4 ng/ml in combination with UCAI score of <3 showed a highly considerable specificity of 98% to discriminate the remission phase of UC (Mayo disease activity index <2), although with a low sensitivity (31%). CONCLUSION: FC appears to be a non-invasive biomarker with moderate accuracy to discriminate the active phase of inflammatory bowel disease (IBD). The value of FC especially in combination with UCAI is highly considerable to rule out the Mayo disease activity index >2.