title: Corticotrophin-releasing hormone and desmopressin tests in the differential diagnosis between Cushing's disease and pseudo-Cushing state: a comparative study.
abstract: BACKGROUND
  We recently proposed a new and effective way of interpreting human corticotrophin-releasing hormone (hCRH) and desmopressin (DDAVP) tests, for the differential diagnosis between Cushing's disease (CD) and pseudo-Cushing state (PC), based on the simultaneous analysis of ACTH and cortisol.
  
  
  OBJECTIVE
  The study had the aims of comparing the diagnostic performance of the two tests and determining whether carrying out both tests was more beneficial than carrying out only one.
  
  
  METHODS
  We studied 30 CD, 18 PC and 12 control (CT) subjects: in these patients, hCRH test, DDAVP test, 24-h urinary free cortisol, serum cortisol after overnight 1-mg dexamethasone suppression test and serum cortisol circadian rhythm were performed.
  
  
  RESULTS
  The hCRH test and the DDAVP test showed an identical and excellent diagnostic performance (sensitivity 96·6% and specificity 100% for both tests); moreover, the hCRH and DDAVP tests showed almost perfect diagnostic agreement (κ = 0·93; P < 0·05) with a significantly higher number of concordant diagnoses (58 cases of 60) than those resulting from all other possible combinations among the studied tests. Interestingly, there were no subjects in whom both hCRH and DDAVP tests gave a simultaneous misdiagnosis.
  
  
  CONCLUSIONS
  Our study indicates that the hCRH and DDAVP tests have similar diagnostic performance and present excellent agreement, without giving simultaneous misdiagnosis in any subject. Because of these characteristics, the use of both tests offers the physician a valuable tool for those cases of hypercortisolism which are difficult to interpret.
authors.affiliation: Division of Endocrinology, Department of Clinical Medicine and Applied Biotechnologies, Polytechnic University of Marche, Torrette, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Tirabassi
authors.forename: Roberta
authors.initials: R
authors.lastname: Papa
authors.forename: Emanuela
authors.initials: E
authors.lastname: Faloia
authors.forename: Marco
authors.initials: M
authors.lastname: Boscaro
authors.forename: Giorgio
authors.initials: G
authors.lastname: Arnaldi
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D003346:Corticotropin-Releasing Hormone / Q000097:blood*; D003894:Deamino Arginine Vasopressin / Q000097:blood*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D047748:Pituitary ACTH Hypersecretion / Q000097:blood* / Q000175:diagnosis*
chemical_list: D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D003894:Deamino Arginine Vasopressin; D006854:Hydrocortisone