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HelpTest Code CORTU Cortisol, Free, 24 Hour, Urine
Necessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Supplies: Urine Tubes, 10-mL (T068)
Submission Container/Tube: Plastic urine tube
Specimen Volume: 5 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. Add 10 g of boric acid as preservative at start of collection.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
CMH COLLECTION: 24 hour urine in urine jug
Specimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 28 days | ||
| Ambient | 7 days |
Useful For
Preferred screening test for Cushing syndrome
Diagnosis of pseudo-hyperaldosteronism due to excessive licorice consumption
Test may not be useful in the evaluation of adrenal insufficiency.
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Day(s) Performed
Monday through Friday
Report Available
2 to 6 daysReporting Name
Cortisol, Free, UReference Values
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
Use the factor below to convert from mcg/24 hr to nmol/24 hr:
Conversion factor
Cortisol: mcg/24 h x 2.76=nmol/24 hr (molecular weight=362.5)
For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html.
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
82530