This study investigated faecal calprotectin concentration, a measure of intestinal inflammation, in infants and children with abdominal pain. Faecal calprotectin was measured by an enzyme-linked immunosorbent assay kit in spot stool samples in 76 infants with typical infantile colic, 7 infants with transient lactose intolerance and 27 healthy infants. All infants were 2-10 wk of age. In addition, 19 children with recurrent abdominal pain (RAP; mean age 11.5 y), 17 with inflammatory bowel disease (IBD; mean age 11.1 y; 10 had Crohn's disease and 7 ulcerative colitis) and 24 healthy children (mean age 5.3 y) were studied. In infants with infantile colic the mean faecal calprotectin concentration was not different from that in healthy infants (278 +/- 105 vs 277 +/- 109 mg kg(-1), p = 0.97) or in infants with transient lactose intolerance (300.3 +/- 124 mg kg(-1), p = 0.60). The calprotectin level was similar in boys and girls and fell significantly with age (p = 0.04). Children with IBD had faecal calprotectin levels (293 +/- 218 mg kg(-1)) much higher than healthy children (40 +/- 28 mg kg(-1), p < 0.0001) and children with RAP without identified organic disease (18 +/- 24 mg kg(-1), p < 0.0001).
Conclusion: Faecal calprotectin may differentiate between functional abdominal pain and IBD in school-aged children. In young infants high faecal calprotectin levels are normal.