Background: Fecal calprotectin is a sensitive marker for gut inflammation. Recently, we have established that a related protein, S100A12, is elevated in the feces of children with inflammatory bowel disease (IBD). This may represent a specific and sensitive disease marker. The objective was to investigate the utility of fecal S100A12, in comparison to fecal calprotectin and standard inflammatory markers, as a screening marker for IBD in children with gastrointestinal symptoms.
Methods: Stool samples were obtained from 61 children presenting with gastrointestinal symptoms requiring endoscopy. Fecal S100A12, calprotectin, and serum S100A12 levels were measured and correlated to final diagnosis and standard tests (ESR, CRP, platelet count, and albumin).
Results: Children diagnosed with IBD (n = 31) had elevated fecal S100A12 (median 55.2 mg/kg) and calprotectin (median 1265 mg/kg) levels compared with the children without IBD (n = 30; S100A12: median 1.1 mg/kg, P < 0.0001; calprotectin: median 30.5 mg/kg; P < 0.0001). The sensitivity and specificity of fecal S100A12 (cutoff 10 mg/kg) for the detection of IBD were both 97%, whereas fecal calprotectin (cutoff 50 mg/kg) gave a sensitivity of 100% and a specificity of 67%.
Conclusions: Both fecal markers were superior to the sensitivities and specificities of any standard inflammatory test. Both fecal S100A12 and calprotectin are sensitive markers of gastrointestinal inflammation, but fecal S100A12 provided exceptional specificity in distinguishing children with IBD from children without IBD. Fecal S100A12 is a simple, noninvasive test that can be used to screen and select children warranting further invasive and laborious procedures such as endoscopy for the investigation of their gastrointestinal symptoms.