Standardization of Growth Hormone and Insulin-like Growth Factor-I Measurements.

Measurement of the levels of growth hormone (GH) and its related factor insulin-like growth factor I (IGF-I) is essential for the diagnosis and treatment of GH deficiency (GHD) and conditions related to excess GH such as acromegaly and pituitary gigantism. Measurement of GH levels is also used as an indicator of hypothalamic-pituitary function. Because of the marked variability in GH measurements among kits, the Study Committee for GH and Its Related Factors of The Foundation for Growth Science, Japan standardized GH values measured with various commercially available GH assay kits in Japan. The committee also established IGF-I reference values for Japanese subjects of all ages, from childhood to adulthood. Hopefully, international harmonization of GH measurements will be achieved in the future.