title: Basal serum cortisol concentration as a screening test for hypoadrenocorticism in dogs.
abstract: BACKGROUND
  Measurement of basal serum or plasma cortisol concentration is used as a screening test for hypoadrenocorticism in dogs, but is not well characterized.
  
  
  OBJECTIVE
  To evaluate the sensitivity and specificity of basal serum cortisol to detect hypoadrenocorticism in a population of dogs with a clinical suspicion of hypoadrenocorticism.
  
  
  METHODS
  Four hundred and fifty dogs with nonadrenal gland illness and 14 dogs with naturally occurring hypoadrenocorticism were included.
  
  
  METHODS
  Retrospective case-control study. The records of all dogs having had an ACTH stimulation test performed between January 2005 and September 2011 at the University of Bristol were reviewed. Dogs were included if the test was performed as a screening for hypoadrenocorticism. The sensitivity and specificity of basal serum cortisol concentration to detect dogs with hypoadrenocorticism were calculated using 2 cut-offs and compared to the gold standard ACTH stimulation test.
  
  
  RESULTS
  Using a cut-off of ≤2 μg/dL (≤55 nmol/L), the sensitivity and specificity of basal cortisol to detect hypoadrenocorticism were 100% and 63.3%, respectively, whereas for a cut-off of ≤1 μg/dL (≤28 nmol/L), the sensitivity and specificity were 85.7% and 91.8%, respectively.
  
  
  CONCLUSIONS
  Measurement of basal serum cortisol is useful as a screening test for hypoadrenocorticism in dogs using a cut-off of ≤2 μg/dL (≤55 nmol/L), and the disease is unlikely with a basal serum cortisol >2 μg/dL (>55 nmol/L). A basal serum cortisol ≤2 μg/dL (≤55 nmol/L) cannot be used to diagnose hypoadrenocorticism, and an ACTH stimulation test should be performed in these cases.
authors: School of Veterinary Sciences, University of Bristol, Langford, Bristol, UK; Small Animal Hospital, Langford Veterinary Services, Langford, Bristol, UK.
authors: C
authors: C
authors: Bovens
authors: K
authors: K
authors: Tennant
authors: J
authors: J
authors: Reeve
authors: K F
authors: KF
authors: Murphy
mesh_terms: D000309:Adrenal Insufficiency / Q000097:blood / Q000175:diagnosis / Q000662:veterinary*; D000818:Animals; D016022:Case-Control Studies; D004283:Dog Diseases / Q000097:blood* / Q000175:diagnosis; D004285:Dogs; D006854:Hydrocortisone / Q000097:blood*; D012189:Retrospective Studies
chemical_list: D006854:Hydrocortisone
keywords: ACTH; Addison's disease; Canine; Endocrine