Biochemical tests in the diagnosis of childhood growth hormone deficiency

GH stimulation tests are widely used in the diagnosis of GH deficiency (GHD), although they are associated with a high false positive rate. We have examined, therefore, the performance of other tests of the GH axis[ urinary GH excretion, serum insulin-like growth factor I (IGF-I), and IGF-binding protein-3 (IGFBP-3) levels] compared with GH stimulation tests in identifying children defined clinically as GH deficient. Group I comprised 60 children (mean age, 10.3 ± 4.8 yr) whose diagnosis of GHD was based on a medical history indicative of pituitary dysfunction (n = 43) or on the typical phenotypic features and appropriate auxological characteristics of isolated GHD (n = 17). Group II comprised 110 short children (mean age, 9.8 ± 4 yr) in whom GHD was not suspected, but needed exclusion. The best sensitivity for a single GH test was 85% at a peak GH cut-off level of 10 ng/mL, whereas the best specificity was 92% at 5 ng/mL. The sensitivities of IGF-I, IGFBP-3, and urinary GH, using a cut-off of− 2 sd score...