The usefulness of serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) for evaluation of children with short stature.

The diagnostic value of serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) was studied in 24 growth hormone deficient (GHD) and 36 normal variant short stature (NVSS) children. The serum IGF-1 and IGFBP-3 concentrations were markedly below the 5th centile for chronological age in all 24 GHD children, but were in the low normal range for age in most of the NVSS children. The concentrations of IGF-1 and IGFBP-3 significantly correlated with peak GH concentration, height age, and bone age. To account for the age- and sex-dependency, IGF-1 and IGFBP-3 levels were transformed to standard deviation score (SDS). Using the -2 SDS as a cut-off level to differentiate between GHD and NVSS, the diagnostic value of IGF, as well as IGFBP-3, showed sensitivity 100 per cent, specificity 66.7 per cent, and accuracy 80 per cent. The combined use of IGF-1 and IGFBP-3 < -2 SDS improved the diagnostic value with sensitivity 100 per cent, specificity 77.8 per cent, and accuracy 86.7 per cent. We concluded that the serum concentrations of IGF-1 and IGFBP-3 could reflect endogenous GH secretion and could be used as a screening evaluation of GH status in short children.