Background: We aimed to study fecal calprotectin in Scottish children with inflammatory bowel disease (IBD) and compare its diagnostic accuracy with blood parameters.Methods: Stool samples from 48 Scottish children (29 males, 19 females) had calprotectin measured at IBD diagnosis. The median age at diagnosis was 11.2 years (interquartile range [IQR] 8.7–13.0 years). There were 33 patients with Crohn's disease, 5 with ulcerative colitis, and 10 with IBD type unspecified. IBD was diagnosed by standard criteria. Calprotectin was measured using a commercially available kit (PhiCal Test) and 47/48 patients had comparative blood results available at diagnosis.Results: The fecal calprotectin concentrations were raised in 96% (46/48) of patients studied. The median calprotectin value was 750 μg/g (IQR 235.8–1251 μg/g). In comparison with standard blood tests, 32/45 (71.1%) had abnormal erythrocyte sedimentation rate, 19/38 (50.0%) had abnormal C-reactive protein, 29/46 (63.0%) had raised platelets, 12/45 (26.7%) had hypoalbuminemia, and 38/46 (82.6%) had abnormal hemoglobin. We identified 7/47 (14.9%) patients with raised calprotectin at diagnosis who did not have any abnormalities detected in the blood tests performed. All 48 patients (100%) had at least 1 abnormal blood test and/or raised calprotectin at diagnosis.Conclusions: Calprotectin is significantly more likely to be raised than any commonly employed blood tests at IBD diagnosis. When used in combination with these bloods tests an abnormality was demonstrated in 1 or both tests in all patients at diagnosis in this study. Fecal calprotectin measurement is a significant advance when used contemporaneously and in addition to a routine panel of blood tests in the diagnosis of pediatric IBD.(Inflamm Bowel Dis 2008)