A cortisol urine test is also called a urinary free cortisol test or UFC test. It measures the amount of cortisol in your urine.
Cortisol is a hormone produced by the adrenal glands, which are located on top of the kidneys. Cortisol is often released in response to physical or emotional stress.
Cortisol functions by:
- controlling blood sugar
- regulating blood pressure
- fighting infections
- playing a role in mood regulation
- playing a role in the metabolism of carbohydrates, fats, and proteins
Cortisol levels naturally rise and fall throughout the day. They’re usually highest in the morning and lowest around midnight, but there are also variations that depend on the person.
When this 24-hour cycle is disrupted, however, the body can produce too much or too little cortisol. A cortisol test can be performed to determine the underlying cause of abnormal cortisol levels.
There are different types of cortisol tests that may be performed, including blood, saliva, and urine tests. The urine test is done over a period of 24 hours.
The cortisol urine test tends to be more comprehensive than the other types of cortisol tests. It measures the total amount of cortisol excreted into the urine over a 24-hour period.
Blood tests or saliva tests, however, only measure cortisol levels at a particular time of day. Some people also find blood tests to be stressful, and since the body releases more cortisol during times of stress, the results may not be as precise.
In some cases, your doctor may order both a cortisol urine test and another type of cortisol test to obtain more accurate results.
Your doctor may order a cortisol urine test if you’re showing symptoms of a medical condition that causes cortisol levels to rise or fall.
Symptoms of high cortisol levels
Cushing syndrome is a collection of symptoms associated with high cortisol levels. The most common symptoms include:
- increased urination
- increased thirst
- fatty tissue deposits, especially in the midsection and upper back
- pink or purple stretch marks on the skin
- weight gain
- fatigue
- muscle weakness
- thinning skin that bruises easily
Women may have irregular periods and excess facial and chest hair. Children may show delayed physical or cognitive development.
Symptoms of low cortisol levels
The symptoms of low cortisol levels often emerge slowly. At first, they may only appear during times of extreme stress, but they’ll gradually increase in intensity over several months.
Potential symptoms include:
- weight loss
- fatigue
- dizziness
- fainting
- muscle weakness
- abdominal pain
- diarrhea
- constipation
When cortisol levels abruptly drop to life-threatening levels, an acute adrenal crisis may occur.
The symptoms of an acute adrenal crisis include:
- darkening of the skin
- extreme weakness
- vomiting
- diarrhea
- fainting
- a fever
- chills
- loss of appetite
- a sudden onset of severe pain in the lower back, abdomen, or legs
Call 911 or your local emergency number if you’re having these symptoms. An acute adrenal crisis is a serious medical emergency that requires immediate treatment.
It’s important to tell your doctor about any prescription drugs or over-the-counter medicines you’re taking. Certain medications can interfere with the accuracy of the cortisol urine test. These include:
- diuretics
- estrogens
- glucocorticoids
- ketoconazole
- lithium
- tricyclic antidepressants
Your doctor may instruct you to stop taking medications that could affect the results. However, you should never stop taking your medications unless your doctor tells you to do so.
A cortisol urine test is a safe, painless procedure that only involves ordinary urination.
Cortisol is measured in a urinary sample collected over a 24-hour period. Your doctor will give you special containers to use for collecting urine samples. They’ll also explain how to collect the urine properly.
On the first day of the urine collection:
- Urinate into the toilet after waking up.
- Flush this first sample away.
- After that, collect all urine in special containers and store them in a cool place.
On the second day of the urine collection:
- Urinate into the container right after waking up. This will be the last sample.
- Return the containers to the appropriate person as soon as possible.
You can also consider ordering a home cortisol testing kit.
If your infant needs to have a cortisol urine test, you’ll collect their urine in a special bag.
The collection procedure is as follows:
- Thoroughly wash the area around your baby’s urethra with soap and warm water.
- Attach the collection bag to the child. For males, place the bag over his penis. For females, place the bag over her labia. Put their diaper on over the collection bag.
- After your baby has urinated, pour the urine sample in the bag into a collection container. Keep this container in a cool place.
- Return the container to the appropriate person as soon as possible.
Collect urine samples over a 24-hour period. It will be necessary to check the bag often throughout the collection period.
Once the urine samples have been collected, they’ll be sent to a lab for analysis.
The results will be sent to your doctor within a few days. Your doctor will discuss your results with you and explain what they mean.
Normal results
A normal adult range for cortisol levels in urine is usually between 3.5 and 45 micrograms per 24 hours. However, normal ranges may vary slightly among different labs.
Abnormal results
Abnormal results could be caused by a number of conditions.
High cortisol levels often indicate Cushing syndrome. This condition may be caused by:
- an overproduction of cortisol due to a tumor of the adrenal gland
- the ingestion of substances that raise cortisol levels, such as alcohol or caffeine
- severe depression
- extreme stress
Low cortisol levels may be caused by an insufficient production of cortisol in the adrenal glands. This is often a result of a condition called Addison’s disease.
People with this disease are also at an increased risk of Addisonian crisis, or acute adrenal crisis, which occurs when cortisol levels drop dangerously low.
Further testing may be necessary to confirm a diagnosis of any of these conditions.