Comparative Evaluation of Calprotectin, C-Reactive Protein and Erythrocyte Sedimentation Rate as Enzymatic Biomarkers in Inflammatory Bowel Disease Activity

Inflammatory bowel disease (IBD) is a common inflammatory disease of the gastrointestinal tract. This study aims to assess the ability of fecal calprotectin (CP) in diagnosis of IBD and compare it with the conventional inflammatory biomarkers. All biochemical and clinical analyses were conducted at the Lagash Land Laboratories, Baghdad, Iraq. Patients of age 18 years or older presenting with gastrointestinal symptoms were enrolled. Blood samples were collected to evaluate physiological levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), ferritin and urea while stool samples were used for fecal CP measurement, fecal occult blood (FOB) testing and Helicobacter pylori infection characterization. Patients were divided into three groups: Group I consisted of patients with CP levels < 50 µg/g and a negative FOB test, group II consisted of patients with CP levels ≥ 50 µg/g and a negative FOB test while group III consisted of patients with CP levels ≥ 50 µg/g and a positive FOB test. IBD diagnosis was confirmed with colonoscopy in group II and III. Box and Whisker plots and Bland and Altman (BA) analysis were used to assess correlation of fecal CP with CRP and ESR, with p-values calculated using unpaired ttest. A total of 317 patients were registered with 150, 69 and 98 patients in group I, II and III. The mean age of patients in Group I, II and III was 43.10 ± 18.31 (range 18-80) years, 49.75 ± 17.63 (range 18-83) years and 46.48 ± 18.57 (range 18-90) years respectively. The mean fecal CP values were higher for both group II and III, as compared to group I (i.e. 207.15 ± 120.75 vs. 27.46 ± 7.37, p< 0.001 and 278.99 ± 119.02 vs. 27.46 ± 7.37, p < 0.001). The difference between median values of (CRP vs. CP) and (ECR vs. CP) was also significant (p < 0.01) for all three groups. BA plots showed no biases. CP levels can better discriminate between IBD patients and healthy controls, compared to CRP and ESR. Moreover, the correlation between fecal CP levels and serum CRP and ESR concentrations was statistically significant.