Comparison of Diagnostic Values of Growth Hormone Stimulation Tests in Adolescents - Original Article

摘要

Objective: Growth hormone (GH) stimulation tests are used in the diagnosis of GH deficiency, therefore, various pharmacological agents are applied for this aim. Since there is no gold standard, usually two tests are performed. We aimed to investigate clinical utilities of four stimulation tests (insulin tolerance test (ITT), clonidine, L-dopa and glucagon) in adolescents with severe short stature. Materials and Methods: Any two or three of four stimulation tests were performed to forty-three subjects (32 males, 11 females) aged 11-20 years with severe short stature. Different numbers of tests were applied to subjects (ITT to all, L-dopa to 32, clonidine to 21 and glucagon to 12 subjects). Responses to clonidine, L-dopa and glucagon tests were compared with response to ITT. In addition, sensitivity, specificity and positive predictive value (PPV) and negative predictive value (NPV) of four tests were calculated. For these analyses, patients with no response to two tests were classified as having growth hormone deficiency (GHD). Results: There were no significant differences in the responses of the three tests when compared with ITT. Glucagon test had 100% sensitivity, specificity, PPV and NPV. Of the other three tests, the specificity (90%) and the PPV (85%) of clonidine test were highest. On the other hand, sensitivities and NPV of ITT (91% and 86% ,respectively) and L-dopa test (94% and 90%, respectively) were higher than clonidine test. Conclusion: Glucagon, L-dopa and ITT should be preferred as the first test since NPV of these tests was high. Turk Jem 2010; 14: 6-9