title: [Reference values for IGF-I, IGFBP-1, IGFBP-3 and osteocalcin in healthy children in Zaragoza].
abstract: 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.
  
  
  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.
authors.affiliation: Hospital Infantil Miguel Servet, Zaragoza, España.
authors.forename: A
authors.initials: A
authors.lastname: Cortés Blanco
authors.forename: J I
authors.initials: JI
authors.lastname: Labarta Aizpún
authors.forename: A
authors.initials: A
authors.lastname: Ferrández Longás
authors.forename: E
authors.initials: E
authors.lastname: Mayayo Dehesa
mesh_terms: D000293:Adolescent; D002391:Catchment Area, Health; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006304:Health Status; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D008297:Male; D015675:Osteocalcin / Q000097:blood*; D011446:Prospective Studies; D011627:Puberty / Q000502:physiology; D012016:Reference Values; D013030:Spain; D014504:Urban Health
chemical_list: D018970:Insulin-Like Growth Factor Binding Protein 1; D018972:Insulin-Like Growth Factor Binding Protein 3; D015675:Osteocalcin; D007334:Insulin-Like Growth Factor I