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Laboratory: Clinical Biochemistry  (AUTOMATED)
Test Name:
CORTISOL, FREE, 24h URINE (Urinary Free cortisol, UFC) - (U)
Test Code: CORU
Clinical Information:
Description: Urinary free cortisol (UFC) used to assess adrenal function and screen for endogenous Cushing’s syndrome. This test is of limited use in assessment of adrenal insufficiency.


Cushing’s screening with UFC is not recommended in patients with renal failure, adrenal incidentaloma / mild disease. During 2nd and 3rd trimester of pregnancy, UFC cut-offs may be 3x ULN due to natural increase.


Patient preparation instructions: This test is unaffected by multivitamins (45 - 125 µg biotin) or biotin-only supplements.

Collection Devices:
Specimen Required:
Urine: 5.0 mL

Collection Information: Collect urine over a 24-hour period in a container with no preservative. Collection container must be stored refrigerated (not frozen) during collection.

PB110-50-01ENG Patient Brochure 24 Hour Urine Collection
Special Processing: Preservatives are not required. Refer to JA110-50-01A 24 Hour Urine Processing Flow Chart

24-Hour volume must be recorded in milliliters. Transfer 3 mL aliquot to standard aliquot tube 12x75 mm. Do not use 10 mL tubes.

Specimen Stability:

Ambient: 24 hours 
Refrigerated:  7 days 

Frozen: 3 months -20ºC, freeze only once

Urine: 5.0 mL

Adult volume: Min 3 mL aliquot in 12x75mm standard aliquot tube.
Refer to JA110-50-01A 24 Hour Urine Processing Flow Chart 


Shipping & Storage: Store and ship frozen. Avoid repeated freeze-thaw cycles.

Testing Laboratory (MB): Health Sciences Centre, Biochemistry lab

Reference Values:
AgeCortisol, 24h urine (nmol/day)
0-2 ynot established
3-8 y5-70

Reference intervals updated effective February 5, 2024.

Method of Analysis: Competitive ECLIA Roche Cortisol III Assay

Once Per Week
See Also:
More Information:
Interpretation & Assay Interferences: At daily therapeutic levels, prednisolone and hydrocortisone caused elevated levels of cortisol