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Cortisol is a hormone produced by the adrenal glands. These glands are located just above each kidney and are responsible for blood pressure regulation and the body's response to stress. The adrenal glands are also responsible for sexual development as well as reproductive health. If there is a cortisol imbalance, any of these functions can be negatively impacted. Cortisol testing is a relatively simple way to determine if there is an imbalance relating to this hormone and can be performed by blood, urine, or saliva testing procedures.
Cortisol testing is most frequently performed by the use of a blood test. It is common to have this test run twice in one day, with one blood sample being taken in the morning and another in the afternoon. Cortisol levels naturally fluctuate during the course of the day, so having these two blood samples can help the doctor determine whether the hormone levels are fluctuating at an appropriate rate.
Performing cortisol testing by using the saliva has become a more popular choice for many patients. With this procedure, all the patient has to do is spit into a test tube. Instead of twice a day as in the blood test, cortisol levels must be measured four times over the course of a day when testing the saliva. The patient typically performs this test at home and then mails the test tubes to the lab for analysis.
Using urine as a form of cortisol testing is another possible method. A 24-hour urine specimen is required for this test. The patient will be given a container to take home and use to collect the urine. The container is generally kept in the refrigerator during the collection time. Once the 24 hours has expired, the patient will return the container to a previously directed location for testing.
It is important to let the doctor know what medications are being taken prior to undergoing cortisol testing, as some medications may cause inaccurate results. Patients are frequently asked to avoid any type of strenuous exercise for a full day prior to cortisol testing. Lying down and resting just prior to the test will often help the test results to be more accurate as well. There is a certain degree of controversy over the effectiveness of saliva or urine cortisol testing compared to blood testing methods. Therefore, many doctors prefer to use the traditional blood tests instead of using a procedure that may be more convenient for the patient.
Saliva testing for cortisol is the most accurate method of cortisol testing as it measures bioavailable hormone, not protein-bound like serum. Saliva testing makes it possible to measure cortisol four times a day, which is important because you can see the cortisol fluctuating throughout the day. You can test saliva at home. You can get a test kit from ZRT Laboratory.