Late-night and low-dose dexamethasone-suppressed cortisol in saliva and serum for the diagnosis of cortisol-secreting adrenal adenomas.
OBJECTIVE
In patients with adrenal incidentalomas, hormonally active masses need to be considered, particularly cortisol-producing adenomas (CPA), aldosterone-producing adenomas, and pheochromocytomas. The screening for hypercortisolism relies on confirming excess cortisol secretion and insufficient suppression after dexamethasone. Because of its high correlation with free cortisol and its stress-free collection, salivary cortisol (SaC) may offer advantages over serum cortisol (SeC). We evaluated the value of SaC and SeC for the diagnosis of CPA. Design Comparative study between 2001 and 2006.


METHODS
Thirty-eight patients with confirmed CPA were compared with 18 healthy subjects as well as 48 control patients suffering from aldosterone-producing adenomas (n=13), pheochromocytomas (n=16), or nonfunctioning adenomas (n=19). Sampling of saliva and serum was performed at 2300 and at 0800 h following low-dose dexamethasone suppression. Receiver operating characteristics analysis was used to calculate thresholds with at least 95% sensitivity for CPA.


RESULTS
Regarding the cutoffs for late-night cortisol, SaC (4.8 nmol/l, sensitivity 97%, specificity 69%) was slightly more specific than SeC (115 nmol/l, sensitivity 97%, specificity 63%). In contrast, the cutoff for dexamethasone-suppressed SaC (3.7 nmol/l, sensitivity 97%, specificity 83%) was slightly less specific than SeC (94 nmol/l, sensitivity 97%, specificity 88%). However, the latter cutoffs demonstrated greater specificity when compared with the cutoffs for late-night cortisol.


CONCLUSIONS
The diagnostic accuracy of SaC is as good as SeC. Owing to its higher specificity, dexamethasone-suppressed cortisol is preferable to late-night cortisol when screening for Cushing's syndrome in patients with adrenal incidentalomas.
Deutschbein
Timo
T
Department of Endocrinology and Division of Laboratory Research, Medical Center, University of Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany.
Unger
Nicole
N
Hinrichs
Jakob
J
Walz
Martin K
MK
Mann
Klaus
K
Petersenn
Stephan
S
D000236:Adenoma / Q000175:diagnosis* / Q000378:metabolism; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D003480:Cushing Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D003907:Dexamethasone / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012463:Saliva / Q000187:drug effects / Q000378:metabolism*; D012680:Sensitivity and Specificity
D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone