Clonidine and glucagon stimulation for testing growth hormone secretion in children and adolescents: Can we make it with fewer samples?

• Published in: Journal of endocrinological investigation Vol. 36; no. 11; pp. 1046 - 1050
• Main Authors: Christoforidis, A., Triantafyllou, P., Slavakis, A., Katzos, G.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-12-2013
• Subjects: Adolescent; Child; Clonidine; Endocrinology; False Positive Reactions; Female; Glucagon; Growth Disorders - diagnosis; Human Growth Hormone - deficiency; Human Growth Hormone - secretion; Humans; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Original Article; Retrospective Studies; Stimulation, Chemical; Clonidine test; growth hormone; glucagon test; children
• ISSN: 0391-4097; 1720-8386
• DOI: 10.3275/9061

Background:
Our aim was to retrospectively evaluate the possibility to reduce the number of GH analyses during clonidine and glucagon tests without compromising accuracy.
Subjects and methods:
Two hundred and forty-five tests were performed in a total of 188 children and adolescents with a mean age of 9.93±2.88 yr in a single center during the last 5 yr.
Results:
Ninety-one out of 158 (57.59%) clonidine tests and 47/87 (54.02%) glucagon tests had at least one sample >10 µg/l (negative). For clonidine tests, not measuring GH at 30 min would have resulted in only one negative test missed (0.63% false positive result), whereas not measuring GH both at 0 and 30 min would have increased the false positive percentage to 2.53%. Ending clonidine tests at 90 min would have resulted in 7 negative tests missed (4.43% false positive results). For glucagon tests, more than half of the tests peaked at 120 min (56.32%). Skipping sampling at 0, 60 and 180 min provided a false positive rate of 5.75%.
Conclusions:
For clonidine tests we can omit blood sampling at time points 0 and 30 min without significantly compromising accuracy.