The 17-OHCS urine test detects an inactive product in the liver called 17-hydroxycorticosteroid. It is produced when the liver breaks down cortisol, a naturally occurring hormone.
The test is most often used to diagnose Cushing syndrome. It can also help detect other conditions that may result in excessive or too little cortisol production.
This test helps measure your cortisol levels. Cortisol is a hormone produced by the adrenal glands. It affects a variety of bodily functions, including:
- bone growth
- stress control
- central nervous system function
When your cortisol level is too high or too low, these functions may be adversely affected. The only way for a doctor to make an accurate diagnosis is to measure your cortisol levels using this test.
The 17-OHCS test is conducted using urine samples. Unlike other urine tests, this one must be completed over a 24-hour span. That means that all the urine you produce in a 24-hour period must be collected in the provided container.
Here are some tips for urine collection:
- start urine collection in the morning
- collect all urine produced that day and at night
- collect the final urine sample the following morning and seal the container
Once you are finished collecting the samples, take the container to a clinical laboratory along with any paperwork your doctor gives you. You may need to write the completion date and time on the outside of the container in permanent marker.
Some testing facilities recommend refrigerating the urine for the best results. Each time you urinate into the container, cap it and place it into the refrigerator. Talk to your doctor about his or her recommendation.
During the collection period, your doctor may ask you to stop taking:
- birth control pills
- estrogen pills
- adrenal gland hormone replacements (dexamethasone)
If you are attempting to collect urine from an infant or toddler, patience is key. Your pediatrician will give you a urine collection bag to place inside his or her diaper. Frequent diaper checks are essential to prevent the contents of the bag from leaking out.
Test results will indicate that your cortisol levels are normal, too high, or too low.
According to the National Institutes of Health, normal values for cortisol over a 24-hour period are:
- 4 to 14 mg for men
- 2 to 12 mg for women (NIH, 2011)
The most common cause of increased cortisol levels is Cushing syndrome. It is caused by adrenal or pituitary tumors that cause the glands to produce and release excess hormones. Patients with extreme emotional or physical stress will also have higher-than-normal 17-OHCS levels.
Other causes of higher-than-normal cortisol levels include:
- hydrocortisone use
- severe hypertension (high blood pressure)
- corticosteroid use
- severe malnutrition
Lower-than-normal cortisol levels may be attributed to:
- enzyme deficiencies
- hypopituitarism (inability of the pituitary gland to produce hormones)
- Addison’s disease (inability of the adrenal gland to produce hormones)
The outlook for 17-hydroxycorticosteroid abnormalities depends on your condition. Because it is a hormonal problem, medications may be prescribed to help limit or stimulate cortisol production. If obesity is the issue, your doctor will recommend a weight loss plan.
17-OHCS determination can be more difficult to assess in pregnant women. The hormones released during pregnancy can skew test results. Generally, this urine test is performed throughout pregnancy to help detect potential hormonal problems.
If abnormal cortisol levels are due to Cushing syndrome, your doctor may recommend surgical removal of your adrenal gland. The surgery can be performed openly (using a large incision) or laparoscopically (using smaller tools and incisions). After removing your adrenal gland, you will need to be monitored regularly for hormonal imbalances. You’ll be given synthetic hormones to replace those produced by the gland.