Cortisol (Dexamethasone Suppression Test) With Reflex to Dexamethasone
CPT:
82533
Synonyms
- Dexamethasone Suppression Test
Test Includes
If the cortisol (503990) result is >1.7 μg/dL, dexamethasone test will be performed. Adequate dexamethasone drug level is confirmed with dexamethasone reflex measurement.
Special Instructions
For more information regarding the administration and interpretation of the dexamethasone suppression test (DST) in the evaluation of patients for Cushing disease/syndrome, please see Dexamethasone Suppression Screening for Cushing Disease/Syndrome in the online Endocrine Appendix.
Expected Turnaround Time
6 - 15 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Information
Related Documents
Specimen Requirements
Specimen
Serum or plasma, frozen
Volume
3 mL
Minimum Volume
1 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (heparin) tube
Collection
Specimen must be separated from cells within one hour of venipuncture. Transfer serum or plasma to a plastic transport tube and freeze. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
Storage Instructions
Freeze.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 2 days |
Refrigerated | 2 days |
Frozen | 1 year |
Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Gross hemolysis
Test Details
Use
A reflex profile that tests adrenal suppression with dexamethasone.
Limitations
False-positive results can be seen in obese individuals, in those who have had a poor night's sleep, and in individuals who are under acute emotional or physical stress.
Methodology
High-pressure liquid chromatography (HPLC)/tandem mass spectrometry (MS-MS)
Reference Interval
Positive: Serum cortisol >1.7 μg/dL after single-dose dexamethasone
References
Magiakou MA, Mastorakos G, Oldfield EH, et al. Cushing's syndrome in children and adolescents. Presentation, diagnosis, and therapy. N Engl J Med. 1994 Sep 8; 331(10):629-636. 8052272
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 503990 | Cortisol Dexamethasone Reflex | 505957 | Cortisol, Serum LCMS | ug/dL | 2143-6 | |
| 503990 | Cortisol Dexamethasone Reflex | 503991 | Dexamethasone Reflex | N/A |
| Reflex Table for Dexamethasone Reflex | ||||||
|---|---|---|---|---|---|---|
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
| Reflex 1 | 500118 | Dexamethasone, Serum | 500119 | Dexamethasone, Serum | ng/dL | 14062-4 |
| Reflex Table for Dexamethasone Reflex | ||||||
|---|---|---|---|---|---|---|
| Order Code | Order Name | Result Code | Result Name | UofM | Result LOINC | |
| Reflex 1 | 500118 | Dexamethasone, Serum | 500980 | Dexamethasone, Serum | N/A | |
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