SAT-357 Cotton Swab-Based Metabolic Signatures of Salivary Cortisol Measured by Liquid Chromatography-Mass Spectrometry

The comprehensive screening assay of salivary cortisol and its metabolic analogs is necessary to evaluate their pathophysiological functions in various adrenal diseases, such as Cushing’s Syndrome (CS). In contrast to the conventional method with Salivette(®), the cotton swab may provides a point-of-care sampling for clinical screening as well as emergency management, and it also takes an advantage of sample preparation protocol. Sample preparation of salivary cortisol and its metabolic analogs was achieved by purification with solid-phase extraction after enzymatic hydrolysis with β-glucuronidase, and the sample was quantitatively measured by liquid chromatography-mass spectrometry (LC-MS) with selective MS scan modes and polarity swithcing. Due to uncertain sample volume in the cotton swab, the metabolic ratio of cortisol to cortisone, corresponding for 11β-HSD activity, may be an alternative marker in addition to individual salivary concentrations of cortisol and its analogs. The metabolic ratios of cortisol to cortisone in control group was higher than those of CS patients (1.93±4.09 vs. 0.66±1.08), while the increased ratios from 0.63±0.99 to 1.26±1.24 were obtained after surgery. The present swab-based LC-MS method may be appropriate for collecting saliva and the metabolic ratios of cortisol to its analogs could be the good screening tool for adrenal diseases.