title: Can a random serum cortisol reduce the need for short synacthen tests in acute medical admissions?
abstract: BACKGROUND
  Short synacthen tests (SSTs) are frequently performed in medical inpatients with suspected adrenocortical insufficiency. The utility of a random or baseline serum cortisol in this setting is unclear. We determined random cortisol thresholds that safely preclude SSTs in acute medical admissions.
  
  
  METHODS
  We analysed SSTs in acute non-critically ill general medical patients (n = 166, median age 66, range 15-94 y; men 48%, women 52%). The SST was defined according to the 30-min cortisol as 'pass' (>550 nmol/L) or 'fail' (< or =550 nmol/L). Receiver operating characteristics (ROC) curves were generated to determine the predictive value of the basal cortisol for a failed SST.
  
  
  RESULTS
  Of 166 SSTs, a pass was seen in 127 (76.5%) tests, while 39 (23.5%) tests failed the SST. ROC curves showed that no single cut-off point of the baseline cortisol was adequately both sensitive and specific for failing the SST despite a good overall predictive value (area under curve 0.94; 95% confidence interval 0.89-0.98). A basal cortisol <420 nmol/L had 100% sensitivity and 54% specificity for failing the SST, while a basal cortisol <142 nmol/L had 100% specificity and 35% sensitivity. Restricting the SST to patients with a basal cortisol <420 nmol/L would have prevented 44% of SSTs while correctly identifying all patients who failed the SST.
  
  
  CONCLUSIONS
  A baseline serum cortisol may prevent unnecessary SSTs in medical inpatients with suspected adrenocortical insufficiency. However, SSTs are still indicated in patients with random cortisol <420 nmol/L, or where the suspicion of adrenal insufficiency is compelling.
authors.affiliation: Department of Endocrinology and Diabetes, Prince Charles Hospital, Cwm Taf Local Health Board, Merthyr Tydfil, Mid Glamorgan CF47 9DT, UK.
authors.forename: R
authors.initials: R
authors.lastname: Kadiyala
authors.forename: C
authors.initials: C
authors.lastname: Kamath
authors.forename: P
authors.initials: P
authors.lastname: Baglioni
authors.forename: J
authors.initials: J
authors.lastname: Geen
authors.forename: O E
authors.initials: OE
authors.lastname: Okosieme
mesh_terms: D000224:Addison Disease / Q000097:blood* / Q000175:diagnosis* / Q000503:physiopathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001774:Blood Chemical Analysis / Q000379:methods* / Q000706:statistics & numerical data; D003955:Diagnostic Tests, Routine; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D055815:Young Adult
chemical_list: D006854:Hydrocortisone