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A cortisol test measures the level of the 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 adrenocorticotropic hormone (ACTH).
Cortisol has many functions. It helps the body use sugar (glucose) and fat for energy (metabolism). It helps the body manage stress. Cortisol levels can be affected by many things, 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 in cortisol levels, you may have overactive adrenal glands.
Cortisol levels vary widely throughout the day, so you collect urine over 24 hours for this test.
A cortisol test is done to find problems of the pituitary gland or adrenal glands, such as making too much hormone.
You may be asked to avoid strenuous physical activity the day before the test.
Be sure to drink enough fluids during the 24-hour urine test. This prevents dehydration.
Many medicines may change the results of this test. Be sure to tell your doctor about all the non-prescription 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? ).
This test does not cause any pain.
Collecting a 24-hour urine sample does not cause problems.
A cortisol test measures the level of the hormone cortisol in a 24-hour sample of urine.
These numbers are just a guide. The range for "normal" varies from lab to lab. Your lab may have a different range. Your lab report should show what range your lab uses for "normal." Also, your doctor will evaluate your results based on your health and other factors. So a number that is outside the normal range here may still be normal for you.
Less than 100 micrograms (mcg) or less than 276 nanomoles (nmol)
5–55 mcg or 14–152 nmol
2–27 mcg or 5–75 nmol
High values of cortisol may be caused by:
You may not be able to have the test, or the results may not be helpful, if:
CitationsPagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.Other Works ConsultedChernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
Current as of: July 28, 2019
Author: Healthwise StaffMedical Review: E. Gregory Thompson MD - Internal MedicineKathleen Romito MD - Family MedicineAlan C. Dalkin MD - Endocrinology
Current as of: July 28, 2019
Author: Healthwise Staff
Medical Review:E. Gregory Thompson MD - Internal Medicine & Kathleen Romito MD - Family Medicine & Alan C. Dalkin MD - Endocrinology
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