The Clinical Significance Of Fecal Calprotectin In Differentiating Functional And Organic Bowel Diseases

Aims:To investigate the value of fecal calprotectin(FC)in the identification of organic bowel disease(OBD)and functional bowel disease(FBD),and the value of identification in inflammatory bowel disease(IBD)and irritable bowel syndrome(IBS).Secondly,to explore the relationship between FC and clinical features of IBD patients,such as colonoscopy,C-reactive protein(CRP),and so on.Methods:According to the study criteria,the patients with intestinal diseases(OBD,IBS and other FBD,IBD)were included,and their clinical data were classified and collected.FC was measured by double antibody sandwiches and colloidal gold immunochromatography semi-quantitative technique.Sensitivity(Sen),specificity(Spe),positive predictive value(PPV),negative predictive value(NPV),accuracy(Acc),and the area under the ROC curve(AUC)of FC for the identification of OBD and FBD,and of IBD and IBS were calculated respectively.The relationship between FC and IBD clinical parameters was analyzed.Results:From October 2016 to January 2018,a total of 441 patients with OBD or FBD were included in this study.Of two hundred and seventy-five OBD patients(194 males and 81 females)with an average age of 37.5±16.2 years and a median duration of 16months(quartiles:4-48 months),160 had IBD(CD 107,UC 53)and 26 cases had suspected IBD.Of 166 FBD patients(93 males and 73 females)with an average age of40.8±15.3 years and the median duration of 18 months(quartiles of 6-60 months),73cases had IBS and 93 cases had non-specific intestinal disorders.(1)When the FC cut-off value(FC-cov)was 15ug/g and 60ug/g,the positive FC rate in OBD patients was 85.82%and 65.09%respectively,which was significantly higher than in FBD group(p=0.000).When FC-cov=15?g/g,the Sen was 85.82%,Spe 55.42%,PPV 76.13%,NPV 70.23%,AUC 70.6%,and Acc 74.38%of FC diagnosing OBD.When FC-cov=60ug/g,the Sen was 65.09%,Spe 81.93%,PPV 85.65%,NPV 58.62%,AUC 73.5%,and the Acc 71.43%of FC diagnosing OBD.(2)When the FC-cov was 15ug/g and 60ug/g,the positive FC rate in IBD patients was86.88%and 68.75%respectively,which was significantly higher than in IBS patients(p=0.000).When FC-cov=15?g/g,the Sen was 86.88%,Spe 49.32%,PPV 79.0%,NPV63.16%,AUC 68.1%,and the Acc 75.11%of FC diagnosing IBD.When FC-cov=60ug/g,the Sen was 68.75%,Spe 80.82%,PPV 88.71%,NPV 54.13%,AUC 74.8%,and the Acc was 72.53%of FC diagnosing IBD.(3)The clinical symptoms(such as abdominal pain,bloating,diarrhea,constipation,hematochezia)were not significantly related to positive FC rate in IBD patients(p>0.05).The positive FC rate was no significant difference among the IBD patients with different disease location(according the Montreal classification)(p>0.05).When FC-cov=60?g/g,FC positive rate was higher in IBD patients with colorectal lesions than in without colorectal lesions(p=0.021).The positive FC rate was significantly positive related with the total numbers of colorectal lesions in IBD patients(r_s=0.295,p=0.000).When FC-cov=60?g/g,the positive FC rate in IBD patients with elevated white blood cell counts was significantly higher than in normal WBC counts(p=0.038).When FC-cov=15ug/g,the median platelet counts in patients with positive FC were higher than in negative FC(p=0.028).The positive FC rate in IBD patients with higher fecal leukocytes or positive fecal OB was higher than in patients with normal fecal test(p<0.05).There was a significant positive correlation between the level of CRP and FC(r_s=0.376,p=0.000).Conclusion:FC may be a first-line indicator to identify intestinal organic diseases and functional diseases.Once a patient has positive FC,further examination is required to eliminate the possibility of organic bowel diseases.