Clinical and Technical Aspects in Free Cortisol Measurement

Abstract

Accurate measurement of cortisol is critical in adrenal insufficiency as it reduces the risk associated with misdiagnosis and supportsthe optimization of stress dose. Comprehensive assays have been developed to determine the levels of bioactive free cortisol andtheir clinical and analytical efficacies have been extensively discussed because the level of total cortisol is affected by changes in thestructure or circulating levels of corticoid-binding globulin and albumin, which are the main reservoirs of cortisol in the human body. Antibody-based immunoassays are routinely used in clinical laboratories; however, the lack of molecular specificity in cortisol assessment limits their applicability to characterize adrenocortical function. Improved specificity and sensitivity can be achieved bymass spectrometry coupled with chromatographic separation methods, which is a cutting-edge technology to measure individual aswell as a panel of steroids in a single analytical run. The purpose of this review is to introduce recent advances in free cortisol measurement from the perspectives of clinical specimens and issues associated with prospective analytical technologies.