Session: SAT 379-412-Cushing's Syndrome
Poster Board SAT-392
Objective: We investigated whether a low basal dehydroepiandrosterone sulphate (DHEAS) level is a sensitive and specific screening test for the detection/exclusion of SH in patients with newly-diagnosed AI.
Patients/methods: 185 consecutive patients with AI referred to our clinic between 2006 and 2013 were screened for clinical and biochemical evidence of adrenal medullary (urinary and plasma metanephrines) and cortical (1 mg dexamethasone suppression test, 24h urinary free cortisol (UFC), serum DHEAS, paired plasma renin and aldosterone) hyperfunction. All positive dexamethasone suppression [>1.8 mcg/dL (50 nmol/L)] and UFC (> upper limit of reference range) results were further investigated, and we diagnosed SH when at least two of the following criteria were met: raised UFC, raised midnight serum cortisol, 48 h dexamethasone suppression test cortisol >1.8 mcg/dL (50 nmol/L). Plasma ACTH was <10 pg/mL (2.2 pmol/L) in all patients with SH.
Results: At presentation, 29 patients (16%) were diagnosed with SH. We calculated an age-and gender-specific DHEAS ratio (derived by dividing measured DHEAS by the lower limit of the respective reference range) for all patients in the cohort and found that a ratio ≤ 1.12 was a sensitive (100%) and specific (91.9%) screening test for the diagnosis of SH. In comparison, a cortisol level after a 1mg dexamethasone suppression test of 1.9 mcg/dL (53 nmol/L) was a sensitive (100%) screening test for SH, but had lower specificity (82.9%). 24 h UFC lacked sensitivity (69%) and specificity (68%).
Conclusion: A single basal measurement of DHEAS offers comparable sensitivity and greater specificity to the existing gold-standard 1 mg dexamethasone suppression test for the detection of SH in patients with AIs.
Nothing to Disclose: MCD, AKA, OP, ASP, JG, AS, DH, MG
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