Cortisol in Urine
A cortisol test is done to measure the level
hormone cortisol in a 24-hour sample of urine. The
cortisol level may show problems with the
adrenal glands or the
pituitary gland. Cortisol is made by the
adrenal glands. Cortisol levels get higher when the
pituitary gland releases another hormone called
adrenocorticotropic hormone (ACTH).
Cortisol has many functions. It helps the body use sugar (glucose) and
fat for energy (metabolism), and it helps the body manage stress.
Cortisol levels can be affected by many conditions, such as physical or
emotional stress, strenuous activity, infection, or injury.
Normally, cortisol levels rise during the early morning hours and are
highest about 7 a.m. They drop very low in the evening and during the early
phase of sleep. But if you sleep during the day and are up at night, this
pattern may be reversed. If you do not have this daily change (diurnal rhythm)
in cortisol levels, you may have overactive adrenal glands. This condition is
Cortisol in urine is measured from all of the urine collected over 24 hours because of the wide variation in cortisol levels that occurs throughout the day.
Why It Is Done
cortisol test is done to find problems of the
pituitary gland or adrenal glands, such as making too much hormone, which
happens in Cushing's syndrome.
How To Prepare
You may be asked to avoid strenuous
physical activity the day before a cortisol test.
Be sure to
drink enough fluids during the 24-hour urine test to prevent
Many medicines may change the
results of this test. Be sure to tell your doctor about all the
nonprescription and prescription medicines you take.
Talk to your doctor about any concerns you have regarding the need
for the test, its risks, how it will be done, or what the results will mean. To
help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).