Cortisol, AM & PM Test

Measures the blood's cortisol levels released in response to stress, in both the morning and afternoon.

 Cortisol levels fluctuate in a circadian pattern with highest levels around 6 AM to 8 AM (0600-0800), and lowest levels in the late evening approaching midnight.

This blood test measures levels of the hormone cortisol in the morning and again in the afternoon to provide feedback on its fluctuation. The hormone cortisol (hydrocortisone) is made by the adrenal glands and is the most prominent glucocorticosteroid. It plays a key role in the maintenance of several body functions.

Cortisol tests can help determine if there is a problem with the adrenal glands or the pituitary gland. Cortisol levels increase when the pituitary gland releases adrenocorticotropic hormone (ACTH). In this test's case, one sample will be taken in the morning and another at night.

Typically, if you have a normal sleep schedule where you wake in the morning and go to sleep at nighttime, cortisol levels rise and fall in conjunction. In the morning, cortisol levels are usually their highest around 7 a.m. In the evening, crtisol levels often drop very low. This may be reversed if your sleep schedule differs.

Increased levels of cortisol can indicate the following:

• Cushing disease (pituitary adenoma producing excessive ACTH which stimulates the adrenal gland to overproduce endogenous cortisol)
• Ectopic Cushing syndrome (tumor outside the pituitary produces ACTH)
• Adrenal gland excess cortisol secretion (due to an adrenocortical carcinoma or benign adrenal hyperplasia)
• Pseudo-Cushing (eg, due to severe depression, alcoholism)

Decreased levels of cortisol:

• Decreased production of cortisol due to adrenal insufficiency, pituitary insufficiency and/or hypothalamic insufficiency

Cortisol levels can be affected by:

• Infection
• Injury
• Stress (Emotional or Physical)
• Strenuous Activity
• Steroid Medications

Typically, the AM blood collection should be done between 7AM and 9AM, while the PM collection should be done between 3PM and 5PM.