Growth hormone (GH) provocative retesting of 108 young adults with childhood-onset GH deficiency and the diagnostic value of insulin-like growth factor I (IGF-I) and IGF-binding protein-3.

Serum levels of total insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) reflect the endogenous GH secretion in healthy children and exhibit little diurnal variation, which makes them good diagnostic markers for screening of GH deficiency (GHD) in short children, although some controversy still exists. In adults, the diagnostic value of IGF-I and IGFBP-3 suspected of GHD has been reported in only a few studies. We performed a GH provocative test, using oral clonidine, in 108 patients who had previously been treated with GH during childhood (73 men and 35 women). Basal IGF-I and IGFBP-3 levels were compared to those in 1237 healthy controls (312 controls >18 yr) as well as to peak GH levels. Seventy-nine patients had peak GH values below a cut-off value of 7.5 μg/L (34 with isolated GHD), whereas 29 patients had a normal GH response (28 with previous isolated GHD), i.e. 45% of patients treated with GH during childhood because of isolated GHD had a normal GH response when retested in a...