Cortisol is a steroid hormone produced and secreted by the adrenal cortex.
Cortisol plays an important role in the metabolism of proteins, lipids, and carbohydrates. It affects blood glucose levels, helps maintain normal blood pressure and regulates the immune system. Cortisol also helps the body manage stress.
Production of the hormone is regulated by the hypothalamus and by the pituitary gland. When the blood Cortisol level falls, the hypothalamus sends CRH (Corticotropin-Releasing Hormone) to the pituitary, which responds by secreting ACTH (Adrenocorticotropic Hormone). ACTH stimulates the adrenal glands to produce and release Cortisol into the bloodstream.
When the Cortisol Test is ordered?
A cortisol test may be ordered when excess or deficient Cortisol production is suspected. E.g. Cushing syndrome – the body produces a large amount of cortisol, and Addison’s disease – insufficient production of cortisol occurs.
Symptoms of Cushing syndrome are:
- Obesity, especially in the trunk and round, red face, sometimes referred to as a moon face
- Thin, fragile skin
- Reddish-purple stretch marks on the abdomen
- Muscle wasting and weakness
- High blood pressure
- High blood sugar
- In women, irregular menstrual periods and increased facial hair
- In children, delayed development and a short stature.
Symptoms of Addison’s disease:
- Weight loss
- Muscle weakness
- Extreme fatigue
- Low blood pressure
- Nausea, Vomiting, Diarrhea
- Abdominal pain
- Darkening of skin (hyperpigmentation)
- Body hair loss
How to prepare for the Test and How the Test is performed?
Since stress affects Cortisol levels, it is advisable to avoid physical activity the day before and be in a restful state. You should also stop taking any medication that might affect Cortisol levels (eg estrogens, androgens, prednisolone, phenytoin, oral contraceptives, hydrocortisone, etc.).
Because Cortisol levels change throughout the day, blood test is usually done twice a day:
- I – In the morning (around 8 a.m.)
- II- In the evening (around 4 p.m.)
Cortisol may also be measured in a urine (24-hour urine sample test) or saliva test.
In this case, samples should be collected between 11 p.m. and midnight (12 p.m.)
The patient must not eat or drink 15-30 minutes before the test.
Normally, Cortisol levels rise in the morning and reduces in the evening. This pattern may change when a person works the night shifts and sleeps at different times of the day. Cortisol levels can be affected by many factors, such as physical or emotional stress, infection, injury, obesity, chronic diseases and different medications.