title: The diagnostic value of late-night salivary cortisol for diagnosis of subclinical Cushing's syndrome.
abstract: BACKGROUND
  Late-night salivary cortisol is a frequently used and easily implemented diagnostically valuable test for the diagnosis of overt Cushing's syndrome. The use of late-night salivary cortisol in the diagnosis of subclinical Cushing's syndrome is somewhat controversial. In this study, we aimed to determine the diagnostic value of late-night salivary cortisol in diagnosing subclinical Cushing's syndrome and compare it with 24-hour urinary free cortisol levels (UFC).
  
  
  METHODS
  The study consisted of 33 cases of subclinical Cushing's syndrome, 59 cases of non-functioning adrenal adenoma, and 41 control subjects. Late-night salivary cortisol and UFC were measured in all the cases. The diagnosis of subclinical Cushing's syndrome was based on combined results of 1 mg dexamethasone suppression test > 1.8 μg/dL and ACTH < 10 pg/mL.
  
  
  RESULTS
  Mean late-night salivary cortisol levels in subjects with subclinical Cushing's syndrome were significantly higher than in subjects with non-functioning adrenal adenoma and the control group (p < 0.001). Using a cut-off value of 0.18 μg/dL, the sensitivity and specificity of late-night salivary cortisol for diagnosing subclinical Cushing's syndrome were determined as 82% and 60%, respectively. Using a cut-off value of 137 μg/day, the sensitivity and specificity of UFC was determined as 18% and 90%, respectively.
  
  
  CONCLUSIONS
  Because the sensitivity of late-night salivary cortisol for the diagnosis of subclinical Cushing's syndrome is limited, using it as the sole screening test for subclinical Cushing's syndrome may lead to false negative results. However, using it as an adjunct test to other tests may be beneficial in the diagnosis of subclinical Cushing's syndrome. (Endokrynol Pol 2016; 67 (5): 487-492).
authors.forename: Idris
authors.initials: I
authors.lastname: Kuzu
authors.affiliation: Namik Kemal University, Faculty of Medicine, Department of Endocrinology and Metabolism. zuhur744@gmail.com.
authors.forename: Sayid Shafi
authors.initials: SS
authors.lastname: Zuhur
authors.forename: Nazan
authors.initials: N
authors.lastname: Demir
authors.forename: Gokce
authors.initials: G
authors.lastname: Aktas
authors.forename: Feyza
authors.initials: F
authors.lastname: Yener Ozturk
authors.forename: Yuksel
authors.initials: Y
authors.lastname: Altuntas
mesh_terms: D003480:Cushing Syndrome / Q000175:diagnosis*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D008297:Male; D012463:Saliva / Q000737:chemistry*; D012680:Sensitivity and Specificity; D014556:Urine / Q000737:chemistry
chemical_list: D006854:Hydrocortisone
keywords: salivary cortisol; screening; subclinical Cushing’s syndrome; urinary free cortisol