Can fecal calprotectin guide the need for colonoscopy in children with suspected polyps?

Polyps are a notable cause of lower gastrointestinal bleeding. Currently, there is no reliable non-invasive biomarker to determine which children should undergo colonoscopy. This study aimed to evaluate fecal calprotectin (FCP) as a potential screening biomarker for colorectal polyps in children undergoing colonoscopy. This retrospective, single-center observational study analyzed children who underwent colonoscopy at the Children's Hospital Zagreb between November 2013 and December 2023. The study included 672 children, 124 (18%) of whom were found to have one or more polyps, while the rest had normal colonoscopy findings. Children with polyps requiring polypectomy were compared to age-, sex-, and date-matched controls with normal colonoscopy. Receiver operating characteristic (ROC) analysis was performed to assess diagnostic accuracy and determine optimal cut-off values. FCP levels were significantly higher in children with polyps than in controls (719.2 ± 1065 vs. 253.5 ± 544 µg/g; p = 0.009). ROC curve analysis yielded an area under the curve (AUC) of 0.727 (95% CI 0.648-0.807). A cut-off value of 20.5 µg/g provided 90% sensitivity, while 741 µg/g achieved 90% specificity. Only 3% of children with polyps had FCP levels below the laboratory cut-off (< 20 µg/g). No correlation was found between FCP levels and polyp size, number, histological type, or location.

Fecal calprotectin may serve as a useful screening tool for identifying children at risk for colonic polyps, potentially guiding decisions about colonoscopy. However, due to its non-specificity and the influence of various confounders, further prospective studies and standardized pediatric cut-offs are needed to validate its clinical utility.

• Benign solitary colorectal polyps are an important cause of gastrointestinal bleeding in children. • Fecal calprotectin levels can be elevated in children with colorectal polyps.

• In the largest pediatric study to date, normal fecal calprotectin levels were found to be rare among children with colorectal polyps; only 3% had FCP values below the laboratory cut-off.. • A fecal calprotectin cut-off of 20.5 µg/g achieved 90% sensitivity, while a cut-off of 741 µg/g corresponded to 90% specificity for detecting intestinal polyps in children..