Cortisol is the most abundant circulating steroid and the major glucocorticoid secreted by the adrenal cortex.  It helps the body use sugar (glucose) and fat for energy (metabolism). It also helps the body manage stress. Cortisol testing helps diagnose Cushing syndrome, primary and secondary adrenal insufficiency as well as other malfunctions of the adrenal and pituitary glands. The following are …