Cortisol

A cortisol blood test measures the level of the hormone cortisol in the blood.  Cortisol is produced by the adrenal glands.  Cortisol levels can indicate problems with the adrenal glands or pituitary gland. Cortisol has numerous functions including playing an important role in metabolism and helping the body manage stress.   Many things can affect cortisol levels in the blood including vigorous activity, infection, injury, and physical or emotional stress.

 

Cortisol levels typically fluctuate during your day rising in the morning and dropping in the evening (or depending on your sleep patterns).  If you do not experience this fluctuation it can be a sign of overactive adrenal glands, a condition called Cushing's syndrome. For this reason two blood tests are typically performed (morning and afternoon/evening).

 

A cortisol blood test is often performed when a person has symptoms that suggest Cushing's syndrome (muscle wasting, muscle weakness, and obesity,) or Addison's disease (fatigue, weakness, increased pigmentation, among others).