Serum insulin-like growth factor-I (IGF-I) reference ranges for chemiluminescence assay in childhood and adolescence. Data from a population of in- and out-patients

Growth Horm IGF Res. 2012 Jun-Aug;22(3-4):134-8. doi: 10.1016/j.ghir.2012.04.005. Epub 2012 May 14.


Background: Insulin-like growth factor I (IGF-I) measurement is widely used for the diagnosis of disorders of GH secretion and sensitivity, and for monitoring of both GH and IGF-I replacement therapies. However, the lack of appropriate reference values obtained from large and representative samples undermines its practical utility.

Objective: To establish IGF-I reference values for a commonly used enzyme-labeled chemiluminescent immunometric assay in a large population of children aged 0 to 18 years.

Design: Cross-sectional analysis of serum IGF-I levels from samples collected in the two major Italian Children's Hospitals.

Subjects and methods: IGF-I was measured using a solid-phase, enzyme-labeled chemiluminescent immunometric assay in 24403 children (50.6% girls) aged 0 to 18 years. Quantile regression coupled to multivariable fractional polynomials was used to produce age- and sex-specific reference values.

Main outcome measure: Age- and sex-specific IGF-I reference values.

Results and conclusion: Reference values for immunometric assay of IGF-I were produced in a large sample of children and adolescents. Prediction equations were provided to automatize their calculations.

MeSH terms

  • Adolescent
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Inpatients*
  • Insulin-Like Growth Factor I / metabolism*
  • Italy
  • Luminescent Measurements / methods
  • Male
  • Outpatients*
  • Reference Values
  • Regression Analysis


  • Insulin-Like Growth Factor I