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Test Code COCRU Cortisol/Cortisone, Free, Random, Urine

Reporting Name

Cortisol/Cortisone, Free, Random, U

Useful For

Investigating suspected Cushing syndrome (hypercortisolism), when a 24-hour collection is prohibitive (ie, pediatric patients).


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

Specimen Required

Container/Tube: Plastic, 10 mL urine tube (T068)

Specimen Volume: 5 mL

Collection Instructions: Collect a random urine specimen.

Specimen Type


Specimen Minimum Volume

3 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Frozen (preferred) 28 days
  Refrigerated  14 days
  Ambient  72 hours

Day(s) and Time(s) Performed

Monday through Friday; 4 p.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Method Name

RCTU: Enzymatic Colorimetric Assay

COCOR: Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Method Description

Deuterated cortisol (d3-cortisol) is added to a 0.1-mL urine specimen as an internal standard. Cortisol, cortisone, and d3-cortisol are extracted from the specimens using online turbulent-flow HPLC and analyzed by liquid chromatography-tandem mass spectrometry using multiple-reaction monitoring in positive mode. The following ion pairs are used for analysis: Cortisol (363.0/121.1); Cortisone (361.0/163.0); d(3)-Cortisol (366.0/121.2). A calibration curve, generated from stripped urine spiked standards, is included with each batch of patient specimens.(Taylor RL, Machacek DA, Singh RJ: Validation of a high-throughput liquid chromatography-tandem mass spectrometry method for urinary cortisol and cortisone. Clin Chem 2002;48:1511-1519

Reference Values



0-2 years: 3.0-120 mcg/g creatinine

3-8 years: 2.2-89 mcg/g creatinine

9-12 years: 1.4-56 mcg/g creatinine

13-17 years: 1.0-42 mcg/g creatinine

≥18 years: 1.0-119 mcg/g creatinine


0-2 years: 3.0-120 mcg/g creatinine

3-8 years: 2.2-89 mcg/g creatinine

9-12 years: 1.4-56 mcg/g creatinine

13-17 years: 1.0-42 mcg/g creatinine

≥18 years: 0.7-85 mcg/g creatinine



0-2 years: 25-477 mcg/g creatinine

3-8 years: 11-211 mcg/g creatinine

9-12 years: 5.8-109 mcg/g creatinine

13-17 years: 5.4-102 mcg/g creatinine

18-29 years: 5.7-153 mcg/g creatinine

30-39 years: 6.6-176 mcg/g creatinine

40-49 years: 7.6-203 mcg/g creatinine

50-59 years: 8.8-234 mcg/g creatinine

60-69 years: 10-270 mcg/g creatinine

≥70 years: 12-311 mcg/g creatinine


Use the conversion factors below to convert each analyte from mcg/g creatinine to nmol/mol creatinine:


Conversion factors

Cortisol: mcg/g creatinine x 413=nmol/mol creatinine

Cortisone: mcg/g creatinine x 415=nmol/mol creatinine


Cortisol molecular weight=362.5

Cortisone molecular weight=360.4

Creatinine molecular weight=149.59

CPT Code Information



LOINC Code Information

Test ID Test Order Name Order LOINC Value
COCRU Cortisol/Cortisone, Free, Random, U In Process


Result ID Test Result Name Result LOINC Value
10328 Cortisol/Creatinine Ratio 11155-9
RCTU Creatinine Conc 2161-8
10329 Cortisone/Creatinine Ratio 30511-0

Reject Due To









Profile Information

Test ID Reporting Name Available Separately Always Performed
RCTU Creatinine Conc No Yes
COCOR Cortisol, Random, U No Yes