CONTEXT:The measurement of cortisol in saliva is a simple, reproducible, and reliable test to evaluate the normal and disordered control of the hypothalamic-pituitary-adrenal (HPA) axis. There are a variety of simple methods to obtain saliva samples without stress, making this a robust test applicable to many different experimental and clinical situations. EVIDENCE ACQUISITION:Ovid Medline and PubMed from 1950 to present were searched using the following strategies: [andand] and [andand]. The bibliographies of all relevant citations were evaluated for any additional appropriate citations. EVIDENCE SYNTHESIS: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. Late-night salivary cortisol measurements are also useful to monitor patients for remission and/or recurrence after pituitary surgery for Cushing's disease. Because it is a surrogate for plasma free cortisol, the measurement of salivary cortisol may be useful during an ACTH stimulation test in patients with increased plasma binding protein concentrations due to increased estrogen, or decreased plasma binding protein concentrations during critical illness. Most reference laboratories now offer salivary cortisol testing. CONCLUSIONS: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.

OBJECTIVES:Salivary cortisol and cortisone at late night and after dexamethasone suppression test (DST) are increasingly used for screening of Cushing's syndrome (CS). We aimed to establish reference intervals for salivary cortisol and cortisone with three liquid chromatography-tandem mass spectrometry (LC-MS/MS) techniques and for salivary cortisol with three immunoassays (IAs), and evaluate their diagnostic accuracy for CS. METHODS:Salivary samples at 08:00 h, 23:00 h and 08:00 h after a 1-mg DST were collected from a reference population (n=155) and patients with CS (n=22). Sample aliquots were analyzed by three LC-MS/MS and three IA methods. After establishing reference intervals, the upper reference limit (URL) for each method was used to calculate sensitivity and specificity for CS. Diagnostic accuracy was evaluated by comparing ROC curves. RESULTS:URLs for salivary cortisol at 23:00 h were similar for the LC-MS/MS methods (3.4-3.9 nmol/L), but varied between IAs: Roche (5.8 nmol/L), Salimetrics (4.3 nmol/L), Cisbio (21.6 nmol/L). Corresponding URLs after DST were 0.7-1.0, and 2.4, 4.0 and 5.4 nmol/L, respectively. Salivary cortisone URLs were 13.5-16.6 nmol/L at 23:00 h and 3.0-3.5 nmol/L at 08:00 h after DST. All methods had ROC AUCs ≥0.96. CONCLUSIONS:We present robust reference intervals for salivary cortisol and cortisone at 08:00 h, 23:00 h and 08:00 h after DST for several clinically used methods. The similarities between LC-MS/MS methods allows for direct comparison of absolute values. Diagnostic accuracy for CS was high for all salivary cortisol and cortisone LC-MS/MS methods and salivary cortisol IAs evaluated.

Importance:Cushing syndrome is defined as a prolonged increase in plasma cortisol levels that is not due to a physiological etiology. Although the most frequent cause of Cushing syndrome is exogenous steroid use, the estimated incidence of Cushing syndrome due to endogenous overproduction of cortisol ranges from 2 to 8 per million people annually. Cushing syndrome is associated with hyperglycemia, protein catabolism, immunosuppression, hypertension, weight gain, neurocognitive changes, and mood disorders. Observations:Cushing syndrome characteristically presents with skin changes such as facial plethora, easy bruising, and purple striae and with metabolic manifestations such as hyperglycemia, hypertension, and excess fat deposition in the face, back of the neck, and visceral organs. Cushing disease, in which corticotropin excess is produced by a benign pituitary tumor, occurs in approximately 60% to 70% of patients with Cushing syndrome due to endogenous cortisol production. Evaluation of patients with possible Cushing syndrome begins with ruling out exogenous steroid use. Screening for elevated cortisol is performed with a 24-hour urinary free cortisol test or late-night salivary cortisol test or by evaluating whether cortisol is suppressed the morning after an evening dexamethasone dose. Plasma corticotropin levels can help distinguish between adrenal causes of hypercortisolism (suppressed corticotropin) and corticotropin-dependent forms of hypercortisolism (midnormal to elevated corticotropin levels). Pituitary magnetic resonance imaging, bilateral inferior petrosal sinus sampling, and adrenal or whole-body imaging can help identify tumor sources of hypercortisolism. Management of Cushing syndrome begins with surgery to remove the source of excess endogenous cortisol production followed by medication that includes adrenal steroidogenesis inhibitors, pituitary-targeted drugs, or glucocorticoid receptor blockers. For patients not responsive to surgery and medication, radiation therapy and bilateral adrenalectomy may be appropriate. Conclusions and Relevance:The incidence of Cushing syndrome due to endogenous overproduction of cortisol is 2 to 8 people per million annually. First-line therapy for Cushing syndrome due to endogenous overproduction of cortisol is surgery to remove the causative tumor. Many patients will require additional treatment with medications, radiation, or bilateral adrenalectomy.