Cortisol, Free, 24 Hour, Urine
Use
Urinary free cortisol measurement over 24 hours by LC‑MS/MS is the preferred screening test for Cushing syndrome, and can assist in diagnosing pseudo‑hyperaldosteronism due to excessive licorice consumption. It is less useful for evaluating adrenal insufficiency. LC‑MS/MS minimizes analytical interferences from carbamazepine and synthetic corticosteroids.
Special Instructions
Not provided.
Limitations
Stress, hospitalization, surgery, alcoholism, depression, and various medications (eg, exogenous cortisone, anticonvulsants) can affect cortisol levels. Renal disease may cause falsely low values. Incorrect collection (under‑ or over‑collection) and pregnancy (levels up to twice normal) may alter results. Exogenous hydrocortisone ingestion may not suppress results. Without additional tests, 24‑hour urinary cortisol cannot reliably diagnose hypocorticalism.
New York Approved
Methodology
Mass Spectrometry (LC‑MS/MS)
Biomarkers
Cortisol
Analyte
LOINC Codes
- 43126-2 - Cortisol Free Pnl 24h Ur
- 14158-0 - Cortis 24h Ur-mRate
- 13362-9 - Specimen collect Time Ur
Result Turnaround Time
2-7 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
5 mL
Minimum Volume
3 mL
Container
Plastic urine tube (10‑mL, T068)
Collection Instructions
Collect urine for 24 hours. Add 10 g of boric acid at start of collection.
Causes for Rejection
All specimens will be evaluated for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 28 days |