Test Code COCOU Cortisol/Cortisone, Free, 24 Hour, Urine
Additional Codes
EPIC: LAB60285
Sunquest: COCOUM
Reporting Name
Cortisol/Cortisone, Free, UUseful For
Screening test for Cushing syndrome (hypercortisolism)
Assisting in diagnosing acquired or inherited abnormalities of 11-beta-hydroxy steroid dehydrogenase (cortisol to cortisone ratio)
Diagnosis of pseudo-hyperaldosteronism due to excessive licorice consumption
This test has limited usefulness in the evaluation of adrenal insufficiency.
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in RochesterSpecimen Type
UrineNecessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Supplies: Urine Tubes, 10-mL (T068)
Submission Container/Tube: Plastic, urine tube (T068)
Specimen Volume: 5 mL
Collection Instructions:
1. Add 10 g of boric acid as preservative at start of collection.
2. Collect urine for a full 24 hours (required) and record the total volume.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
3 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Special Instructions
Reference Values
CORTISOL
0-2 years: not established
3-8 years: 1.4-20 mcg/24 h
9-12 years: 2.6-37 mcg/24 h
13-17 years: 4.0-56 mcg/24 h
≥18 years: 3.5-45 mcg/24 h
CORTISONE
0-2 years: not established
3-8 years: 5.5-41 mcg/24 h
9-12 years: 9.9-73 mcg/24 h
13-17 years: 15-108 mcg/24 h
≥18 years: 17-129 mcg/24 h
Use the factors below to convert each analyte from mcg/24 h to nmol/24 h:
Conversion factors
Cortisol: mcg/24 hours x 2.76=nmol/24 h (molecular weight=362.5)
Cortisone: mcg/24 hours x 2.78=nmol/24 h (molecular weight=360)
For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Monday through Friday
CPT Code Information
82530-Cortisol; free
82542
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
COCOU | Cortisol/Cortisone, Free, U | 101319-2 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
8546 | Cortisol, U | 14158-0 |
10327 | Cortisone, U | 14044-2 |
TM93 | Collection Duration (h) | 13362-9 |
VL47 | Volume (mL) | 3167-4 |
Clinical Information
Cortisol is a steroid hormone synthesized from cholesterol by a multienzyme cascade in the adrenal glands. It is the main glucocorticoid in humans and acts as a gene transcription factor influencing a multitude of cellular responses in virtually all tissues. Cortisol plays a critical role in glucose metabolism, maintenance of vascular tone, immune response regulation, and in the body's response to stress. Its production is under hypothalamic-pituitary feedback control.
Only a small percentage of circulating cortisol is biologically active (free), with the majority of cortisol inactive (protein bound). As plasma cortisol values increase, free cortisol (ie, unconjugated cortisol or hydrocortisone) increases and is filtered through the glomerulus. Urinary free cortisol (UFC) correlates well with the concentration of plasma free cortisol. UFC represents excretion of the circulating, biologically active, free cortisol that is responsible for the signs and symptoms of hypercortisolism. UFC is a sensitive test for the various types of adrenocortical dysfunction, particularly hypercortisolism (Cushing syndrome). A measurement of 24-hour UFC excretion, by liquid chromatography-tandem mass spectrometry (LC-MS/MS), is the preferred screening test for Cushing syndrome. LC-MS/MS methodology eliminates analytical interferences including carbamazepine (Tegretol) and synthetic corticosteroids, which can affect immunoassay-based cortisol results.
Cortisone, a downstream metabolite of cortisol, provides an additional variable to assist in the diagnosis of various adrenal disorders, including abnormalities of 11-beta-hydroxy steroid dehydrogenase (11-beta HSD), the enzyme that converts cortisol to cortisone. Deficiency of 11-beta HSD results in a state of mineralocorticoid excess because cortisol (but not cortisone) acts as a mineralocorticoid receptor agonist. Licorice (active component glycyrrhetinic acid) inhibits 11-beta HSD and excess consumption can result in similar changes.