title: Clonidine and glucagon stimulation for testing growth hormone secretion in children and adolescents: can we make it with fewer samples?
abstract: BACKGROUND
  Our aim was to retrospectively evaluate the possibility to reduce the number of GH analyses during clonidine and glucagon tests without compromising accuracy.
  
  
  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.
authors.affiliation: 1st Paediatric Department, Aristotle University, Thessaloniki, Greece. christoforidis @doctors.org.uk.
authors.forename: A
authors.initials: A
authors.lastname: Christoforidis
authors.forename: P
authors.initials: P
authors.lastname: Triantafyllou
authors.forename: A
authors.initials: A
authors.lastname: Slavakis
authors.forename: G
authors.initials: G
authors.lastname: Katzos
mesh_terms: D000293:Adolescent; D002648:Child; D003000:Clonidine; D005189:False Positive Reactions; D005260:Female; D005934:Glucagon; D006130:Growth Disorders / Q000175:diagnosis*; D019382:Human Growth Hormone / Q000172:deficiency* / Q000378:metabolism; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013268:Stimulation, Chemical
chemical_list: D019382:Human Growth Hormone; D005934:Glucagon; D003000:Clonidine