A New Immunofluorescence Assay for Fecal Calprotectin Distinguishes Inflammatory Bowel Disease from Functional Bowel Disease

Lixia Xu,Peisi Rao,Zhirong Zeng,Xin Liu

doi:10.4236/ojgas.2018.811042

Abstract

Aims: To investigate the diagnostic value of fecal calprotectin (FC) determined by a new immunofluorescence assay-fluorescence enzyme immunoassay (FEIA) in patient with inflammatory bowel disease (IBD) or functional bowel disease, compared with the typical ELISA kit. Methods: FC was determined simultaneously by FEIA and an ELISA kit in 26 patients with functional bowel disease and 77 patients with IBD. We compared the difference of FC levels between patients with IBD and patients with functional bowel disease. Receiver operating characteristics curve (ROC) was constructed to obtain the optimal cut-off value of FC for distinguishing IBD from functional bowel disease and the corresponding sensitivity and specificity. Results: The median FC levels of patients with IBD in clinical active stage or clinical remission stage was significantly higher than that of patients with functional bowel disease. The median FC levels of patients with IBD in clinical active stage, IBD in clinical remission stage and functional bowel disease were as follow: 699.91 (346.14 ~ 1647.54) μg/g; 407.36 (121.81 ~ 878.48) μg/g; 39.04 (12.09 ~ 81.04) μg/g when FC was measured by FEIA. The median FC levels were 716.99 (240.42 ~ 1232.53) μg/g; 338.46 (53.08 ~ 692.82) μg/g; 41.44 (11.77 ~ 73.19) μg/g among such above three groups of patients respectively, when FC was measured by ELISA kit. The diagnostic value of IBD with FC determined by FEIA (optimal cut-off = 131.79 μg/g) and ELISA kit (optimal cut-off = 121.85 μg/g) presented an area under the curve of 0.881 and 0.873, respectively. Conclusions: FC determined by FEIA was an accurate surrogate marker to distinguish IBD from functional bowel disease.

Highlights

Inflammatory bowel disease (IBD) is a group of non-specific chronic intestinal inflammation of unknown etiology, including ulcerative colitis (UC) and Crohn’s disease (CD)
We have developed a new automatic fecal calprotectin (FC) detection kit using fluorescence enzyme immunoassay (FEIA) which can quickly and accurately detect FC in a short time
We aimed to evaluate the assay in the differential diagnosis between inflammatory bowel disease (IBD) and functional bowel disease, and further to explore whether it can be used as an important screening test

Summary

Introduction

Inflammatory bowel disease (IBD) is a group of non-specific chronic intestinal inflammation of unknown etiology, including ulcerative colitis (UC) and Crohn’s disease (CD). The major symptoms of IBD are abdominal pain, diarrhea, bloody mucopurulent stool and weight loss. Most IBD patients only have manifestations similar to functional bowel disease, such as mild diarrhea and abdominal pain, making it difficult for differential diagnosis. The current differential diagnosis of IBD and functional bowel disease depends on endoscopy. Endoscopy is an invasive examination that patients may have complications such as perforation, hemorrhage, and infection. Patients have to take laxatives to clean the intestines before examination, which is painful with low acceptance. It is in urgent need to find a non-invasive indicator of intestinal inflammation to help clinicians quickly distinguish IBD from functional bowel disease

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Results

Conclusion