Cortisol Test Preparation

Submitted by Medical Health Test Team on October 16, 2012

The cortisol is a hormone produced by the adrenal cortex. The production and internal secretion of cortisol is accelerated by the ACTH (adrenocorticotrophic hormone), a secretion made by the endocrinal gland, a tiny organ composed of glands belonging to the endocrine system situated just below the brain. Cortisol is necessary to accomplish a variety of functions in the body. It is useful in breaking down protein, blood sugar, and triglycerides, maintaining the right blood pressure, and modulating the immune system. A number of factors are known to influence the concentrations of cortisol in the blood including extreme temperatures of heat and cold, severe infection, traumatic conditions, intense exercise, obesity and chronic disorders. In order to test for levels of cortisol in the blood, a sample of the blood is taken once in the morning at 8 am, and then in the evening again at 4 pm. It should be mentioned that conventional values may be reversed in people who are employed during the night and rest during the day for extended periods of time.

When screening for cortisol levels, through a urine test, a 24-hour urine specimen is acquired, preserved in refrigeration, and sent to the pathology laboratory for scrutiny.

The person being tested for cortisol levels must abstain from food and drink for not less than 9 hours before the test, which should commence by 10 am till 7 am. The test must not be administered if the patient is on medication containing corticosteroids, pregnenolone, or supplements containing adrenal extracts as such drugs are likely to influence test results.

Increased stress as well as recent treatment with isotope scans can unnaturally enhance cortisol levels and may nullify test results. Synthetic corticosteroids used to treat high blood pressure, birth control devices, glycyrrhiza glabra, estrogen, androgenic hormone (including DHEA) and progestin therapy can also impress upon cortisol and aldosterone test results. If aldosterone is to be induced, sodium chloride in foods as well as foods containing substantial quantities of salt must be refrained for at least 24 hours prior to screening. The absence of salt for 24 hours could cause the levels of aldosterone to ascend as far as possible.

In some cases, a saliva sample is also used to test for cortisol levels. Even though a saliva sampling is less nerve-wracking than a blood test, it calls for special care in acquiring the specimen. In many instances, the sample is gathered between 10:30 pm and midnight, the period of time when cortisol is generally at its least, to help study Cushing's syndrome.

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