Normal values of serum IGF-1 in adults: results from a Brazilian population

Arq Bras Endocrinol Metabol. 2010;54(5):477-81. doi: 10.1590/s0004-27302010000500008.


Objective: To determine the normal values of serum IGF-1 (Immulite 2000) in a Brazilian adult (21-70 years) population.

Subjects and methods: Healthy volunteers were divided into 10 groups according to age (5-year intervals), with 100 subjects (50 men and 50 women) per group. One-hundred participants were selected for repetition of the test after 12 weeks.

Results: No difference in IGF-1 values was observed between men and women, but a progressive reduction of serum IGF-1 with age was seen. The reference values provided by the manufacturer of the assay, although discretely higher, were very close to the values found in this study. A second measurement of IGF-1 after 12 weeks revealed a variation < 20% in 99% of subjects.

Conclusions: This study established the reference range for IGF-1 determined with the Immulite 2000 assay for a large number of healthy Brazilian adults stratified according to age, and suggests that variations > 20% in IGF-1 levels within an interval of 12 weeks cannot be attributed to interassay variability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Brazil
  • Female
  • Humans
  • Insulin-Like Growth Factor I / analysis*
  • Male
  • Middle Aged
  • Reference Values
  • Sex Factors
  • Young Adult


  • Insulin-Like Growth Factor I