CORTISOL (BLOOD)

Cortisol blood tests are used to help diagnose Cushing syndrome and Addison disease, ;which are adrenal disorders.

Cushing syndrome is caused by too much cortisol, while Addison disease is caused by damage to the adrenal, and is associated with too little cortisol.

Cortisol blood tests are usually taken at about 8-9 am, when blood cortisol concentrations should be at their peak. Sometimes a second sample may be taken late in the evening, about midnight, when cortisol should be at its lowest concentration in the blood.

Cortisol is a steroid hormone, produced by the adrenal gland. Cortisol is involved in the following functions and more:

Proper glucose metabolism
Regulation of blood pressure
Insulin release for blood sugar maintanence
Immune function
Inflammatory response

The production and secretion of cortisol is stimulated by ACTH (adrenocorticotropic hormone) which is produced by the pituitary gland.

Although stress isn’t the only reason that cortisol is secreted into the bloodstream, it has been termed the stress hormone because it's also secreted in higher levels during the body's 'fight or flight' response to stress, and is responsible for several stress-related changes in the body.