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Test Code CORTU Cortisol, Free, 24 Hour, Urine

Reporting Name

Cortisol, Free, U

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.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

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.


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

Reference Values

0-2 years: not established

3-8 years: 1.4-20 mcg/24 hr

9-12 years: 2.6-37 mcg/24 hr

13-17 years: 4.0-56 mcg/24 hr

≥18 years: 3.5-45 mcg/24 hr

 

Use the factor below to convert from mcg/24 hr to nmol/24 hr:

 

Conversion factor

Cortisol: mcg/24 hours 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 13362-9
VL47 Urine Volume 3167-4

Report Available

2 to 6 days

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)

Secondary ID

8546

Urine Preservative Collection Options

Note: The addition of preservative must occur prior to the start of the collection or application of temperature controls must occur during collection.

Ambient (no additive)

No

Refrigerate (no additive)

OK

Frozen (no additive)

OK

50% Acetic Acid

OK

Boric Acid

Preferred

Diazolidinyl Urea

No

6M Hydrochloric Acid

No

6M Nitric Acid

No

Sodium Carbonate

No

Thymol

No

Toluene

No