[Reference values for IGF-I, IGFBP-1, IGFBP-3 and osteocalcin in healthy children in Zaragoza].

OBJECTIVE: Our aim was to estimate reference values for basal serum concentrations of insulin-like growth factor (IGF)-I, IGF binding protein (IGFBP)-1, IGFBP-3 and osteocalcin in healthy children of Zaragoza.

PATIENTS AND METHODS: The reference population consisted of healthy children between 0 and 14 years of age with normal weight and height and living in the metropolitan area of Zaragoza (Spain). It was a transversal study. Immunoradiometric assays were used to determine basal serum IGF-I, IGFBP-1, IGFBP-3 and osteocalcin concentrations. Reference values and ranges were estimated according to the recommendations of the International Federation of Clinical Chemistry.

RESULTS: Reference values have been classified according to age, sex and pubertal stage. IGF-I, IGFBP-1, IGFBP-3 and osteocalcin concentrations differ during the pubertal period according to age. There are differences in IGF-I, IGFBP-3 and osteocalcin levels between prepuberty and puberty and differences in IGF-I and osteocalcin levels among the pubertal stages. Sex did not influence IGF-I or IGFBP-1 concentrations and there were punctual differences in IGFBP-3 and osteocalcin levels between girls and boys.

CONCLUSIONS: Sincere there are differences in IGF-I, IGFBP-1, IGFBP-3 and osteocalcin reference values according to age, sex, pubertal stage and immunoassays, it is necessary to establish the reference values for each population and laboratory in accordance with these parameters.