The diagnostic accuracy of fecal calprotectin during the investigation of suspected pediatric inflammatory bowel disease.

Objectives: Fecal calprotectin (FC) is elevated in patients with inflammatory bowel disease (IBD). Studies evaluating FC during the initial investigation of children with suspected IBD have been limited, especially with regard to their small patient groups. We aimed to evaluate the diagnostic accuracy of FC in a large regional cohort of children undergoing full upper and lower endoscopy for suspected IBD, comparing FC with six common blood parameters.

Methods: Using a retrospective case-control design all FC measurements carried out between 2005 and 2010 in children <18 years old were obtained. All IBD and non-IBD patients who had a FC measurement available before full endoscopic evaluation for suspected bowel inflammation were examined. FC was measured using the PhiCal Test. Multivariate analyzes and receiver operating characteristic curve generation were used to derive significance.

Results: A total of 190 patients (91 IBD and 99 non-IBD controls) met the inclusion criteria. Median FC at diagnosis for the IBD group was 1,265 μg/g (interquartile range (IQR) 734-2,024 μg/g), compared with 65 μg/g (IQR 20-235 μg/g) in controls (P<0.001). FC levels did not vary significantly between patients with Crohn's disease, ulcerative colitis, and IBD unclassified and were not influenced by age or disease location. FC was found to be far superior to commonly utilized blood parameters such as C-reactive protein and white cell count (both P<0.01), with an area under the curve of 0.93 (95% confidence interval 0.89-0.97).

Conclusions: This study demonstrates that FC is an invaluable tool in determining those children who may require endoscopy for suspected IBD, and elevated values should prompt further investigation.