Background: Calprotectin is a protein abundant in neutrophils. Fecal calprotectin can be used as a marker of gastrointestinal inflammation, and an improved assay has recently been developed. The aim of this study was to establish reference values for fecal calprotectin in healthy children aged between 4 and 17 years.
Methods: Fecal samples were obtained from 117 healthy children classified into four age groups: 4 to 6 years, 7 to 10 years, 11 to 14 years, and 15 to 17 years. A health questionnaire was used to ensure that these children fulfilled the inclusion criterion and did not have intercurrent disease, nasal or menstrual bleeding, or nonsteroidal anti-inflammatory drug medication before the sampling period. Calprotectin was analyzed using a quantitative enzyme-linked immunosorbent assay (Calprest, Eurospital SpA, Trieste, Italy). Children with fecal calprotectin values >50 microg/g were asked to deliver an additional sample.
Results: The overall median fecal calprotectin concentration was 13.6 microg/g (95% confidence interval, 9.9-19.5 microg/g) in the 117 children. In the different age groups, 4 to 6 years, 7 to 10 years, 11 to 14 years, and 15 to 17 years, the median calprotectin concentrations were 28.2, 13.5, 9.9, and 14.6 microg/g, respectively. Of these children, 104 (89%) had a concentration <50 microg/g. The remaining 13 children with a calprotectin concentration >50 microg/g delivered one additional fecal sample. All showed a lower concentration in the second sample except for one teenager who later proved to have proctitis.
Conclusions: The suggested cutoff level for adults (<50 microg/g) can be used for children aged from 4 to 17 years regardless of sex. A fecal calprotectin concentration >50 microg/g warrants follow-up.