In conclusion we recommend the overnight dexamethasone suppression test with measurement of salivary cortisol as a screening test for Cushing's syndrome.
late-night salivary cortisol yields sensitivity of 92-100% and specificity of 93-100%. Wow! not much in medicine even approaches this kind of validity.
Endocrine society clinical practice guideline's state proves validity of salivary cortisol testing. Statement: "the diagnostic sensitivity and specificity is said to be excellent (92-100%)" and " Measurement of salivary cortisol by ELISA and LC-MS/MS has been well validated in the United States"
cortisol may act as a mineralocorticoid when in excess, perhaps by saturating the 11β-hydroxysteroid-dehydrogenase (11β-HSD2 enzyme) that inactivates cortisol at the renal tubule
high cortisol levels may be the principal cause of hypokalemic alkalosis
this study showed salivary cortisol to be an "excellent" means to evaluate both those with adrenal disease and adrenal dysfunction. Salivary test is a good tool to evaluate the free active cortisol.
Morning salivary cortisol is as good as serum as screening test for patients with Addison's disease and nighttime salivary cortisol is more adequate than serum in the screening of Cushing's syndrome.
Measurement of an elevated late-night (2300 to 2400 h) salivary cortisol has a greater than 90% sensitivity and specificity for the diagnosis of endogenous Cushing's syndrome
It is expected that the use of the measurement of salivary cortisol will become routine in the evaluation of patients with disorders of the HPA axis.
Late-night salivary cortisol measurement yields excellent overall diagnostic accuracy for Cushing's syndrome, with a sensitivity of 92-100% and a specificity of 93-100%