Significance:
Measuring free cortisol and cortisone are used to determine low-renin hypertension via apparent mineralocorticoid excess. A genetic defect (11HSDB2) or acquired enzyme inhibitor (e.g. glycyrrhizic acid [from natural licorice]) may be to blame.
References:
16. http://www.questdiagnostics.com/hcp/intguide/EndoMetab/EndoManual_AtoZ_PDFs/Cortisone_Serum.pdf
