Pediatric reference intervals for serum copper and zinc

Background: Copper and zinc are essential trace elements and nutrients, which have important roles in physiology and disease and as cofactors in many metabolic pathways. We established age- and gender-specific reference intervals for serum copper and zinc, with a large healthy pediatric population. Methods: A total of 2115 clinically healthy children, 85.4% Caucasian, were enrolled: 1098 boys and 1017 girls 0.5-18 y. Serum copper and zinc concentrations were measured by inductively coupled plasma-mass spectrometry (analytical measurement range: 10-400 mu g/dl for each). Statistical analyses and related calculations were performed using the STATA Statistical software and R software. Results: There were no significant effects of gender or fasting status. For copper, but not zinc, there were significant differences in the reference intervals by age. Based on the central 95% and 95% confidence intervals, the resulting reference interval determined for serum zinc was 64-124 mu g/dl. The age-dependent reference intervals for serum copper were 75-153 mu g/dl for those <10.3 y, 64-132 mu g/dl for those 10.3-12.5 y and 57-129 mu g/dl for those >12.5 y. Conclusions: Our data defined reference intervals for serum copper and zinc in an American, clinically healthy, pediatric population. (C) 2011 Elsevier B.V. All rights reserved.