Screening Tests for Cushing's Syndrome: Urinary Free Cortisol Role Measured by LC-MS/MS

Abstract

Measuring UFC by liquid chromatography tandem-mass spectrometry achieves the best accuracy in diagnosing CS among patients presenting with suspected hypercortisolism.

Diagnostic accuracy of increased urinary cortisol/cortisone ratio to differentiate ACTH‐dependent Cushing's syndrome

“…The Endocrine Society's Clinical Practice Guidelines recommend screening for CS with UFF measurement, preferably using highly accurate methods such as HPLC or LC‐MS/MS, which are reliable in clinical practice to diagnose CS . Using those methods, UFE is easily available, as cortisone can be measured simultaneously with cortisol …”

Clinical utility of late-night and post-overnight dexamethasone suppression salivary cortisone for the investigation of Cushing’s syndrome

“…18,19 The more stringent cut-off of <50 nmol/L sacrifices specificity for sensitivity. 20,21 In this study, we adopted a double cut-off as proposed by the European Society of Endocrinology Clinical Practice Guideline in collaboration with the European Network for the Study of Adrenal Tumors 15 ; the rationale being that a more sensitive cut-off should be employed in those with a higher pretest probability of Cushing's syndrome, such as the presence of an adrenal adenoma on imaging studies. 22 A more specific cut-off can be employed in general to avoid overdiagnosis.…”

Diagnosis and Differential Diagnosis of Cushing’s Syndrome

“…The New England Journal of Medicine T h e ne w e ngl a nd jou r na l o f m e dicine cortisol excretion of 62 μg per day or more has a positive likelihood ratio of 11. 24 Thus, in a patient presenting with obesity, hypertension, type 2 diabetes, and hirsutism who has thin skin, osteopenia, ecchymoses, and an elevated urinary free cortisol level, the probability of Cushing's syndrome is 1 (100%). For such patients, the clinician should move directly to a differential diagnostic evaluation.…”