II. Indications: Cushing's Syndrome Screening
- Preferred among 3 first line options for Cushing's Syndrome Screening
III. Mechanism
- Measures Urine 17-Ketosteroid Excretion and Urine 17-Hydroxysteroid Excretion
IV. Technique
- Collect urine for 24 hours
- Start in the morning after first void
- Continue to collect urine until the next morning and include the first morning void
- Obtain urine Cortisol and Urine Creatinine
- Perform at least twice due to variability (discrepant in 50% of samples)
V. Interpretation: Normal
- Free Urine Cortisol: 10-84 mcg/24 hours (up to 110 mcg/24 hours in some reference ranges)
VI. Causes: Increased (especially if 4x normal range)
VII. Causes: False Positives
- Incorrect urine collection
- Pregnancy
- Excessive fluid intake (>5 Liters/day)
- Pseudo-Cushing's Syndrome
-
Drug Interactions
- Carbamazepine
- Fenofibrate
- Estrogen
- Licorice
- Carbenoxolone
VIII. Causes: False Negatives
- Incorrect urine collection
- Impaired Renal Function (eGFR <60 ml/min)
- Low level Cushing's Syndrome
IX. Efficacy
- Relies on complete and accurate urine collection
- Often falsely normal in adrenal hypercortisolism (use Dexamethasone suppression instead)
- Perform at least twice due to variability (discrepant in 50% of samples)
- Test Sensitivity: 80 to 98%
- Test Specificity: 45 to 98%
Images: Related links to external sites (from Bing)
Related Studies
| Concepts | Laboratory Procedure (T059) |
| SnomedCT | 167399007, 144631002, 269886006 |
| English | Urine free cortisol 24hr.assay, 24-hour urine free cortisol measurement (lab test), urine cortisol, free, 24 hr, urine cortisol, free, 24 hour, 24-hour urine free cortisol measurement, 24 hour urine cortisol, free, Cortisol - 24hr. urine, Urine cortisol 24hr assay &/or free (procedure), Urine cortisol 24hr assay &/or free, Cortisol - 24 hour urine, 24 Hour Urine Free Cortisol Test, Urine free cortisol 24 hour assay (procedure), Urine free cortisol 24 hour assay |
| Spanish | prueba de cortisol libre en muestra de orina de 24 horas (procedimiento), prueba de cortisol libre en muestra de orina de 24 horas |
Ontology: Cortisol measurement, free, urine (C0474662)
| Concepts | Laboratory Procedure (T059) |
| SnomedCT | 389714004, 390446009, 144619004, 167385008, 22820002 |
| CPT | 80420 |
| Italian | Cortisolo libero urinario |
| Dutch | urinair vrij cortisol, vrij cortisol urine |
| Portuguese | Cortisol livre urinário, Cortisol livre na urina |
| Japanese | 尿中遊離コルチゾール, ﾆｮｳﾁｭｳﾕｳﾘｺﾙﾁｿﾞｰﾙ |
| English | urine free cortisol measurement (lab test), urine cortisol, free, urine free cortisol measurement, Urinary free cortisol, Cortisol free urine, free cortisol urine, urinary free cortisol, cortisol free levels urine, urine free cortisol, Measurement of free cortisol in urine, Urine free cortisol level (procedure), Urine free cortisol titer, Urine free cortisol titre, UFC - Urine free cortisol level, Urine free cortisol level, Cortisol measurement, free, urine (procedure), Cortisol measurement, free, urine |
| Czech | Kortizol volný v moči, Volný kortizol v moči |
| Hungarian | Kortizol szabad vizeletszint, Vizelet szabad kortizol |
| Spanish | medición de cortisol libre en orina (procedimiento), medición de cortisol libre en orina, Cortisol libre en orina |
| French | Cortisol libre urinaire |
| German | freies Kortisol im Urin |
Ontology: 24 Hour Urine Cortisol Test (C1255084)
| Concepts | Laboratory Procedure (T059) |
| English | 24 Hour Urine Cortisol Test |
