title: Comparative validation of the growth hormone-releasing hormone and arginine test for the diagnosis of adult growth hormone deficiency using a growth hormone assay conforming to recent international recommendations.
abstract: BACKGROUND
  The GHRH plus arginine (GHRH+Arg) test is a promising alternative to the insulin tolerance test (ITT) for diagnosis of adult GH deficiency (AGHD).
  
  
  OBJECTIVE
  The objectives of the study were to validate the GHRH+Arg test for diagnosis of AGHD, using the ITT as comparator and a GH assay calibrated according to recent international recommendations, and to study the repeatability and tolerance of both tests.
  
  
  METHODS
  This was a multicenter, randomized, open-label, phase III study.
  
  
  METHODS
  The study was conducted at 10 French university hospitals.
  
  
  METHODS
  Sixty-nine subjects (38 and 15 with high and low probability of GH deficiency, respectively, and 16 healthy controls) were randomized: 35 to the GHRH+Arg-GHRH+Arg-ITT test sequence and 34 to the ITT-ITT-GHRH+Arg test sequence.
  
  
  METHODS
  Each subject underwent three tests of GH secretion separated by 24 h or more.
  
  
  METHODS
  The primary variable used for response assessments was serum peak GH response. Test results were compared with the final AGHD diagnosis.
  
  
  RESULTS
  Peak GH responses in the two tests were strongly correlated. A cutoff value of 7.89 microg/liter for GHRH+Arg corresponding to 3 microg/liter for ITT was calculated. The cutoff value leading to 95% specificity with the GHRH+Arg test was measured at about 3.67 microg/liter (sensitivity 79.0%). Intermethod agreement and repeatability were high. Both tests were well tolerated. A preference for the GHRH+Arg test was expressed by 74% of subjects.
  
  
  CONCLUSIONS
  The GHRH+Arg test demonstrated good accuracy and repeatability, was at least as sensitive as the ITT, and was associated with better subject acceptability. The GHRH+Arg test represents a good alternative to the ITT for the diagnosis of AGHD.
authors.affiliation: Unité Mixte de Recherche S693, Faculté de Médecine Paris-Sud, Université Paris-Sud 11, Institut National de la Santé et de la Recherce Médicale Unité 693, Service d'Endocrinologie et des Maladies de la Reproduction, Hôpital de Bicêtre, Assistance Publique-Hôpitaux de Paris, 78 Rue du Général Leclerc, Le Kremlin-Bicêtre 94275, France. philippe.chanson@bct.aphp.fr
authors.forename: Philippe
authors.initials: P
authors.lastname: Chanson
authors.forename: Anne
authors.initials: A
authors.lastname: Cailleux-Bounacer
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Kuhn
authors.forename: Georges
authors.initials: G
authors.lastname: Weryha
authors.forename: Olivier
authors.initials: O
authors.lastname: Chabre
authors.forename: Françoise
authors.initials: F
authors.lastname: Borson-Chazot
authors.forename: Séverine
authors.initials: S
authors.lastname: Dubois
authors.forename: Caroline
authors.initials: C
authors.lastname: Vincent-Dejean
authors.forename: Thierry
authors.initials: T
authors.lastname: Brue
authors.forename: Christine
authors.initials: C
authors.lastname: Fedou
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Bresson
authors.forename: Pierre
authors.initials: P
authors.lastname: Demolis
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Souberbielle
mesh_terms: D000293:Adolescent; D000328:Adult; D001120:Arginine; D005260:Female; D013007:Growth Hormone-Releasing Hormone; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency*; D006801:Humans; D007018:Hypopituitarism / Q000097:blood / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric
chemical_list: D019382:Human Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine