Also Known as: Cortisol test
What is a cortisol blood test?
Cortisol is a hormone that affects almost all of your body's organs and tissues. Your adrenal glands, which are two tiny glands positioned above the kidneys, produce cortisol. The hypothalamus in the brain and the pituitary gland, a small organ below the brain, regulates the hormone's production. When the cortisol level drops in the blood, the hypothalamus releases corticotropin-releasing hormone (CRH), which stimulates the pituitary gland to create ACTH ( adrenocorticotropic hormone). The adrenal glands are stimulated by ACTH to generate and release cortisol. The brain, pituitary, and adrenal glands must all be operating properly in order to produce enough levels of cortisol. A cortisol test determines how much cortisol is present in your blood. If your cortisol levels are abnormally high or low, you may have an underlying adrenal gland problem. If left untreated, these conditions can become life-threatening. Cortisol is an important hormone that assists you in doing the following tasks:
- Responding to stress and infection
- Regulating blood sugar levels.
- Keeping your blood pressure in check.
Controlling your metabolism (the process by your body consumes food and energy)
What is the test used for?
A cortisol test is used to help detect adrenal gland disorders most commonly Cushing's syndrome which is a disorder in which your body produces too much cortisol and Addison’s disease in which your body produces insufficient cortisol. Cortisol is a hormone that regulates protein, lipid, and carbohydrate metabolism, among other functions. Cortisol levels in the blood normally increase and fall in a "diurnal variation" pattern, peaking early in the morning, declining during the day, and reaching its lowest level around midnight.
In some cases due to abnormal findings of cortisol levels the healthcare provider may order additional testing to help confirm the finding and determine the cause.
Dexamethasone Suppression Tests: involves analyzing cortisol levels in a baseline sample, then administering oral dexamethasone (a synthetic glucocorticoid) and detecting cortisol levels in timed samples by suppressing ACTH production.
Testing for Insufficient Cortisol Production: An ACTH stimulation test may be ordered if a health practitioner feels that the adrenal glands are not producing enough cortisol or if initial blood tests reveal insufficient cortisol production.ACTH stimulation is a test that measures the amount of cortisol in a person's blood before and after a synthetic ACTH injection. Cortisol levels will rise in response to ACTH stimulation if the adrenal glands are functioning normally. Cortisol levels will be low if they are damaged or not working properly.
Why and when do you need this test?
If you have symptoms of Cushing's syndrome or Addison's disease, you may require a cortisol test.
Cushing's syndrome causes the following symptoms:
- Obesity, especially in the trunk
- High Blood pressure (Hypertension)
- High Blood sugar ( glucose)
- Fragile skin and purple abdominal streaks
- Muscle weakness and wasting
- Menstrual Irregularities
- Increased facial hair
- Women may experience irregular menstruation cycles and facial hair growth.
This test may also be ordered when someone exhibits the following symptoms of low cortisol levels due to adrenal insufficiency or Addison’s disease.
- Loss of weight
- Muscle weakness
- Pain in the abdomen
Skin discoloration (more common in Addison disease but not in secondary adrenal insufficiency)
- Low blood pressure
- Vomiting and nausea
- Reduced body hair
You may also need a cortisol test if you have signs of an adrenal crisis( a life-threatening condition that occurs when cortisol levels are dangerously low). An adrenal crisis manifests itself in the following ways:
- Blood pressure that is extremely low
- Severe Vomiting
- Severe Diarrhoea
- Severe sudden pain in abdomen, lower back, and legs
- Loss of consciousness
What kind of sample is required for the test?
A small needle will be used by a healthcare professional to obtain a blood sample from a vein in your arm. A small amount of blood will be collected into a test tube or vial once the needle is inserted. When the needle goes in or out, it may sting a little. It normally takes less than five minutes to complete this process. The timing of a cortisol test is critical because cortisol levels fluctuate throughout the day. A cortisol blood test is normally done twice a day, once in the morning when cortisol levels are highest and again in the evening when cortisol levels are lowest.
Do you need to prepare for the test?
Because stress can raise cortisol levels, you may need to take some time off before your test. If there are any special instructions to follow, your health care provider will inform you.
Are there any risks to this test?
Having a blood test carries relatively little risk. You may experience little pain or bruising where the needle gets inserted, but most symptoms disappear quickly.
What do the test results mean?
Cortisol levels that are too high may indicate Cushing's syndrome, whereas cortisol levels that are too low may indicate Addison’s disease or another type of adrenal disease. If the person examined responds to an ACTH stimulation test and has insufficient cortisol, the problem is most likely due to insufficient ACTH production by the pituitary. If the person does not respond to the ACTH stimulation test, the problem is most likely to be with the adrenal glands. Secondary adrenal insufficiency occurs when the adrenal glands are underactive as a result of pituitary dysfunction or insufficient ACTH synthesis. Adrenal damage causes decreased cortisol production, which is referred to as primary adrenal insufficiency or Addison disease.
Once an abnormality has been identified and linked to the pituitary gland, adrenal glands, or another cause, the healthcare provider may use additional testing such as CT (computerized tomography) or MRI (magnetic resonance imaging) scans to pinpoint the source of the excess (such as the pituitary, adrenal, or other tumors) and evaluate the extent of any gland damage. . If your cortisol levels are abnormal, it does not always mean you have a medical problem that needs to be addressed. Infection, stress, and pregnancy can all have an impact on your results. Cortisol levels can also be influenced by birth control pills as well as other medications. Should you have any questions it is always recommended to consult your healthcare provider about your results.