Bioanalytical Methods for Cortisol Analysis

Cortisol is one of the steroid hormone often referred as “stress biomarker” used in diagnosis of diseases or disorder related to elevated chronic stress, pituitary-adrenal, and hypothalamic, especially Cushing’s syndrome and Addison’s disease. It plays an important role in regulating wide range of physiological and pathological body process. Measurement of cortisol levels in human blood, serum or plasma and urine is routinely performed in clinical laboratories by utilizing various immunoassay techniques.
Salivary and sweat cortisol have drawn increasing attention as they reflect biologically active cortisol level and involve non-invasive sampling procedure. Whereas, measurement of cortisol in hair provides reliable information as it reflects cortisol level over the preceding period of 3-4 months (similar to glycated hemoglobin test), which tells average blood sugar level over the past 2-3 months. The 11ß-hydroxysteroid hydrogenase-2 (11ß-HSD2) isoenzyme, which interconverts biologically active cortisol to inactive cortisone, regulates cortisol metabolism. Monitoring the cortisol-cortisone ratio is consider as the best indicator for treating people with adrenal diseases. High-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) is usually employed for the simultaneous measurement of cortisol and cortisone reliably. Studies shown that there are no appreciable correlations between serum, saliva, or urine cortisol levels and hair cortisol concentration. However, a serum cortisol level comparison between stimulated serum cortisol and salivary or urine cortisol demonstrated a positive relationships.