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HelpTest Code Epic LAB382 Cortisol, Free, 24 Hour, Urine
Additional Codes
SQ code UCORTM
Mayo code CORTU
Reporting Name
Cortisol, Free, USpecimen Type
UrinePerforming Laboratory
Mayo Clinic Laboratories in Rochester
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.
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.
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 |
Special Instructions
Reference 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.
Day(s) Performed
Monday through Friday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
82530
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CORTU | Cortisol, Free, U | 43126-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8546 | Cortisol, U | 14158-0 |
| TM93 | Collection Duration (h) | 13362-9 |
| VL47 | Volume (mL) | 3167-4 |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Method Description
The cortisol and cortisone are extracted from the resulting supernatant by an online extraction utilizing high-throughput liquid chromatography. This is followed by conventional liquid chromatography and analysis on a tandem mass spectrometer equipped with a heated nebulizer ion source (APCI). Deuterated cortisol (d4-cortisol, d7-cortisone) is added to a 0.1 mL sample as an internal standard. Cortisol, Cortisone and d4-cortisol are extracted from the specimens using online turbulent flow high-performance liquid chromatography extraction.(Unpublished Mayo method)