Calprotectin as a fecal marker for diagnosis and follow-up in patients with ulcerative colitis

Abstract

Objective This study is designed to evaluate the role of fecal calprotectin as a marker for the diagnosis of ulcerative colitis (UC) and its correlation with disease activity and remission. Background Inflammatory bowel diseases (IBD) are lifelong intestinal inflammatory conditions of unknown etiology, characterized by remissions and exacerbations. The diagnosis and classification of IBD is usually established by a combination of tests (laboratory, endoscopic, and/or radiologic) in the presence of clinical symptoms. Fecal calprotectin serves as a noninvasive biomarker of intestinal inflammation, and has been found to be useful in the diagnosis of IBD, assessment of response to medical therapy, and in prediction of clinical relapse. Materials and methods This study was carried out on 40 patients. Twenty of these patients had clinical, laboratory, colonoscopic, and histopathological findings of UC. Group I was subdivided as follows: GIa: 20 patients with active UC and GIb: the same patients as in GIa while on remission. Group II included 20 patients as controls, matched for age and sex without clinical, laboratory, colonoscopic, and histopathological findings of UC. Complete stool analysis, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) titer, complete blood count, colonoscopy and biopsy, histopathological examination of biopsy specimens, measurement of ulcerative colitis activity index (UCAI), and quantitative determination of calprotectin in stool sample were carried out for all patients. Results There was a highly significant increase in the mean value of fecal calprotectin in active UC patients in comparison with the inactive UC patients and controls. Also, there was a highly significant increase in the mean value of fecal calprotectin in the inactive UC patients in comparison with the controls. There was also a highly significant positive correlation between fecal calprotectin and UCAI, CRP, ESR, total leukocyte count, and platelets count. At the cut-off value of 131 μg/g, fecal calprotectin has 100% accuracy, sensitivity, specificity, positive predictive value, and negative predictive value in differentiating UC patients from other patients with lower gastrointestinal symptoms and at the cut-off value of 253 μg/g fecal calprotectin has 95% accuracy, sensitivity, specificity, positive predictive value, and negative predictive value in differentiating active from inactive UC patients. Conclusion Fecal calprotectin is a valuable, simple, easily performed, and cost-effective noninvasive marker for evaluation of patients with UC. It differentiated UC and other diseases causing colonic symptoms (cut-off value of 131 μg/g) and between active and inactive UC (cut-off value of 235 μg/g) with high accuracy, sensitivity, and specificity. It also correlates well with other markers for UC activity (UCAI, ESR, CRP, total leukocyte count, and platelets count) and could be a reliable surrogate marker for the severity of UC.