Endocrine Abstracts

Short synacthen tests (SST) are used to investigate patients with suspected HPA pathology and a rise of serum total cortisol > 550nmol/L is accepted as demonstrating sufficient cortisol reserve. However, cortisol is 80% bound to cortisol binding globulin (CBG) and therefore abnormal values of CBG can influence serum total cortisol used to interpret dynamic tests of the HPA axis. The free cortisol index (FCI) is a surrogate marker for serum free cortisol and is defined as s...