Urinary Cortisol Quantitation Using Ultra High Pressure Liquid Chromatography/Compact Mass Spectrometry

Introduction

Cortisol is an important steroid hormone produced from cholesterol in the adrenal cortex. Its secretion is closely regulated by Adrenocorticotropic hormone (ACTH). Most cortisol is protein-bound, and only unbound cortisol is excreted in urine. Measurement of cortisol in urine is typically used in the diagnosis of Cushing’s syndrome, a disorder of hypercortisolism.

Although immunoassay methods have extremely high sensitivity, they are subject to variable interferences from other steroids and their conjugates. Liquid chromatography with tandem mass spectrometry is increasingly used in clinical analysis because of its higher specificity and selectivity than immunoassay methods. A simple and robust UHPLC/MS method will be introduced for urinary cortisol analysis and the dynamic range and sensitivity (LOD and LLOQ) of the UHPLC/CMS method will be evaluated.