Usefulness of Serum IGF-I and IGFBP-3 Levels in Children with Short Stature / 임상검사와정도관리

ABSTRACT

BACKGROUND: Serum insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) levels are known markers of growth hormone (GH) secretion. The clinical utility of serum IGF-I and IGFBP-3 testing, however, remains controversial. The aims of this study were to evaluate the usefulness of IGF-I and IGFBP-3 as indicators of GH secretion through the GH stimulation test and to investigate whether a decrease in serum IGF-I levels in children with short stature, regardless of the cause, can be used as a screening test for short stature. METHODS: A total of 262 children presented with short stature, precocious puberty, or premature thelarche and were grouped into 7 tiers based on the 2007 growth chart. Serum IGF-I and IGFBP-3 levels and GH stimulation were analyzed using an immunoradiometric assay, and the data from 68 children who were below the 3rd percentile for height were used to evaluate the usefulness of IGF-I and IGFBP-3 as markers of GH status. RESULTS: GH deficiency was confirmed by the GH stimulation test in 25 of the 68 children, and 15 (15/25, 60%) and 4 (4/25, 16%) of them showed a decrease in IGF-I and IGFBP-3 levels, respectively. The sensitivity and specificity for predicting GH secretion were 60% and 16%, respectively, for IGF-1 and 41.9% and 97.7%, respectively, for IGFBP-3. Decreased serum IGF-I levels were more frequently observed in children below the 25th percentile than in those in the 25th to 95th percentiles. CONCLUSIONS: IGF-I and IGFBP-3 levels have been used as a screening tool for GH secretion in children with short stature, but based on the results of the GH stimulation test in the current study, the levels of IGF-I and IGFBP-3 might not be useful as markers of GH secretion. Evaluating serum IGF-I levels alone is not a sufficient screening test for children with a short stature.