Last Updated December 20th, 2021
What is a cortisol test?
Cortisol test (usually a blood test, though urine and saliva can also be used) is used to measure the levels of the steroid hormone cortisol in your body.
What is cortisol?
Cortisol is a hormone belonging to the category of glucocorticoids secreted by the adrenal glands. This hormone is responsible for-
– Maintaining homeostasis of the body by regulating metabolism including blood sugar and blood pressure.
– Fighting infections
– Preparing the body for stress.
What is the hypothalamic-pituitary-adrenal axis?
The hypothalamic–pituitary–adrenal axis (HPA axis) is accountable for your body’s stress response. Cortisol is released by the adrenal glands under the directions of another hormone known as adrenocorticotropic hormone (ACTH) secreted by the pituitary gland. The release of ACTH is in turn controlled by the hypothalamic release of corticotropin-releasing factor (CRF). When the levels of cortisol reach a certain limit, the negative feedback to the hypothalamus and the pituitary inhibits more release of the stress hormone. CRH (hypothalamus)- ACTH (pituitary)-Cortisol (adrenal).
Why has my physician asked me to undergo a cortisol test?
A cortisol test is a quantitative test that measures the amount of cortisol in your body. Your physician may ask you to undergo a cortisol test if you present with signs and symptoms of cortisol excess or deficiency. The signs of cortisol excess (commonly seen in Cushing’s disease) include-
– Elevated blood pressure
– Elevated blood sugar
– Muscle or bone weakness
– Irregularities of menstruation (in women)
– The tendency of your skin to easily bruise
– Purple striae on your abdomen, thighs or buttocks
– Increase in facial hair (in women)
The signs of cortisol deficiency (seen in Addison’s disease) include-
– Unexplained loss of weight
– Musculoskeletal pain
– Pain abdomen
– Decreased libido in women
– Low blood pressure
Do I need to fast before a serum cortisol test?
No, there is no need to fast before a serum cortisol test.
Can I undergo a cortisol test if I am pregnant?
Yes, you can undergo a cortisol test if you are pregnant or breastfeeding your child.
Can children undergo a cortisol test?
Yes, children can undergo a cortisol test as it is a safe, quick to perform and risk- free test.
How should I prepare for a cortisol test?
No specific preparations are required for a cortisol test. As stress can lead to an increase in cortisol levels, avoid strenuous exercise before this test. Try to get a good night’s sleep. Lie down for about 30 minutes before the test to soothe your nerves.
Inform your physician if you suffer from any coagulopathy or are taking any blood thinners. Many medications including steroids can change the cortisol levels in your blood. Inform your physician in detail if you are taking any medication-allopathic, ayurvedic or homeopathic.
Are there any risks involved in the cortisol test?
A blood cortisol test is a safe, risk-free test. As it is a blood test, it involves withdrawing a blood sample from a vein on your arm. This procedure may elicit pain and lead to dizziness in some patients. You can prefer to look away when blood is being withdrawn if you are faint-hearted. A bruise, bleeding, hematoma or subsequent infection at the site of invasion of the vein may be a complication. Consult your doctor if these problems persist.
How is a cortisol blood test performed?
A blood cortisol test is performed as an outpatient procedure. The test can be carried out in a doctor’s office or at a diagnostic center. If you already are admitted to a hospital, it can be undertaken in the hospital itself, given that the laboratory is equipped to do so. It is a safe, minimally invasive and quick test.
No sedation is given. The technician will apply a tourniquet proximally to the site chosen for venipuncture. This makes the veins more prominent, allowing easier access. The area is cleaned with a disinfectant. A sterile needle is used to puncture the vein and draw about 5 ml of blood.
The pressure is applied to the vein with sterile gauze after the needle is withdrawn. The tourniquet is released. The blood sample is collected in a vial. A small bandage is applied over the site from where blood has been drawn.
The levels of cortisol in your blood do not remain constant throughout the day- they are highest in the morning and lower in the evening. Therefore, a blood cortisol test is performed twice a day. The morning sample is taken at around 7 am in the morning and the second sample is taken at 4 pm in the evening.
How is a urine cortisol test performed?
Your physician will ask you to collect a 24-hour urine sample in order to conduct a urine cortisol test. The rationale remains the same-urine cortisol levels fluctuate during the day. You need to follow the instructions carefully while collecting a urine sample as the results may get affected if you deviate from the prescribed steps, which are-
– Void urine on the morning of the test and ensure that your bladder is empty. Jot down the time in a diary.
– During the next 24 hours, collect all your urine in a container (given to you by your physician).
– Make sure that the sample is not exposed to extreme heat (to prevent the decay of urine).
– Hand over the container to your physician the next day.
How is the saliva cortisol test performed?
Unlike the blood cortisol and the urine cortisol test, a saliva test for cortisol is usually done at night (in-home settings). You will be provided a kit for the same. You need to follow a few simple steps-
– For half an hour prior to the test, you are not supposed to eat, drink or even brush your teeth.
– The ideal time for collecting a sample is between 11 pm and 12 midnight.
– Put the swab (a part of the test kit) in your mouth and keep on rolling it in your mouth for about 2 minutes.
– Ensure that the swab is covered in your saliva.
– Without touching the swab with your fingers, spit it into the container (also a part of the kit).
The sample is to be deposited with the physician or the laboratory the next day.
How long does the cortisol test take?
A cortisol test takes about 10-15 minutes. However, in cases where venous access is difficult (young obese children or geriatric patients), multiple pricks may be required, leading to prolongation of the duration of the test.
What do the results of a cortisol test convey?
The results of a cortisol test may differ depending on your age, gender, medical history, the method used, any medicines that you might be consuming, and the standards employed by the laboratory. The normal ranges for cortisol are:
For 7 a.m. test.: 10 to 20 micrograms per deciliter (mcg/dL),
Around 4 p.m.: 3 to 10 mcg/dL.
Any variation in these values points towards a disorder of the HPA axis. Further testing is required to ascertain the cause of the cortisol increase or decrease.
What factors can affect the actual results of my cortisol test?
Apart from the diurnal variation discussed earlier, many factors can affect the cortisol levels of your body.
– Exogenous administration of steroids can alter the cortisol levels.
– Any stressful condition including infection or inflammation in the body can lead to increased cortisol levels.
– Multiple conditions including pregnancy, obesity, hepatic or renal disorders, and hyperthyroidism can lead to increased cortisol levels.
– Young women produce lower levels of cortisol in response to stress as compared to their male counterparts. The scenario gets reversed with aging.
What is the cost of a cortisol test in India?
A blood cortisol test costs between Rs 500-750 in India. The actual cost may vary depending on the city you live in.
What are the advantages and limitations of a cortisol test?
|It is a minimally invasive, risk-free and easy to perform test.||It can only detect an increase or decrease in cortisol levels. For a diagnosis to be made, further testing is required.|
|Pregnant women and breastfeeding mothers can undergo this test.||The levels of cortisol can be affected by multiple factors.|
|It is safe to be performed on children||It involves puncturing a vein for sample collection. Not recommended in patients on blood thinners or those suffering from a coagulopathy.|
|It is a pocket-friendly test.||A dynamic study of the HPA axis is not provided.|
What are the other tests to analyze cortisol levels?
Dexamethasone suppression test-It is used to evaluate Cushing syndrome by assessing the lack of suppression of the hypothalamic-pituitary-adrenal (HPA) axis by exogenously administered corticosteroids.
ACTH stimulation test- It is used to diagnose Addison’s disease (adrenal insufficiency). It measures the capability of the adrenal glands to respond to ACTH by producing cortisol aptly.
A CT scan or an MRI are the diagnostic modalities routinely employed to detect abnormalities in the glands that from a part of the HPA axis.
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