A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Cortisol, Free, 24-Hour Urine w/ Creatinine by LCMS
Test CodeAlias/See Also
CPT Codes
82530, 82570
Includes
CPT code 81050 may be added at an additional charge for volume measurement
Preferred Specimen
Minimum Volume
Other Acceptable Specimens
Instructions
Record 24-hour urine volume on test request form and urine vial.
Note: Reference ranges do not apply to random urine samples.
Transport Container
Transport Temperature
Specimen Stability
Refrigerated: 21 days
Frozen: 3 months
Methodology
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)
Setup Schedule
Reference Range
Adult | 4.0-50.0 mcg/24 hrs |
Pediatric | |
1-4 Years | 0.9-8.2 mcg/24 hrs |
5-9 Years | 1.0-30.0 mcg/24 hrs |
10-13 Years | 1.0-45.0 mcg/24 hrs |
14-17 Years | 3.0-55.0 mcg/24 hrs |
Cortisol, Free, Urine
Adult | 3.1-42.3 mcg/g creat |
Creatinine, 24-Hour Urine
<3 Years | Not established |
3-8 Years | 0.10-0.80 g/24 hours |
9-12 Years | 0.20-1.40 g/24 hours |
13-17 Years | 0.40-1.90 g/24 hours |
>17 Years | 0.50-2.15 g/24 hours |
Clinical Significance
This urinary free cortisol (UFC) test, performed with a 24-hour urine specimen, is one of the preferred tests for screening for and diagnosing Cushing syndrome. This test may also be used to monitor for recurrence of Cushing disease [1]. In addition, when used in conjunction with the measurement of 24-hour urine cortisone, this test may help identify disorders caused by impaired activity of 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2), such as apparent mineralocorticoid excess (AME) syndrome [2].
UFC level is independent of corticosteroid-binding globulin and albumin levels; thus, UFC level can demonstrate increased bioavailable cortisol in patients with endogenous Cushing syndrome [1]. A UFC test with 24-hour urine specimen also has the advantage of averaging circadian and ultradian variations of cortisol secretion. An elevated UFC level may provide initial evidence for Cushing syndrome. Two or more positive results of UFC tests may establish the diagnosis of Cushing syndrome if non-neoplastic hypercortisolism (pseudo-Cushing syndrome) is excluded [1].
A late-night salivary cortisol (LNSC) test or dexamethasone suppression test (DST) can also be used to diagnose Cushing syndrome or monitor for Cushing disease. Choice of test should be based on clinical scenario [1]. When monitoring for recurrence of Cushing disease, UFC levels usually become abnormal after LNSC tests or DSTs do [1].
UFC testing is not recommended for screening for Cushing syndrome in individuals with impaired kidney function or polyuria [1]. Non-neoplastic hypercortisolism caused by obesity, psychiatric disorders, alcohol use disorder, and polycystic ovary syndrome may increase UFC levels.
In patients with AME syndrome, deficiency of 11beta-HSD2 impairs the deactivation of cortisol to cortisone. Similarly, ingestion of certain compounds that inhibit 11beta-HSD2 activity, such as glycyrrhetinic acid (in licorice), carbenoxolone, and phthalates, may also reduce the conversion of cortisol to cortisone. Therefore, a high cortisol-to-cortisone ratio measured in 24-hour urine may help identify disorders caused by impaired activity of 11beta-HSD2 [2, 3].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
Reference
1. Fleseriu M, et al. Lancet Diabetes Endocrinol. 2021;9(12):847-875.
2. Young WF, Jr., et al. Endocrine Reviews. 2017;38(2):103-122.
3. Carvajal CA, et al. J Clin Endocrinol Metab. 2020;105(4):dgz315.
Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
33608 Ortega Highway |
San Juan Capistrano, CA 92675-2042 |
Last Updated: March 28, 2024