Dexamethasone, Serum
Use
Dexamethasone is a synthetic glucocorticoid with significant anti-inflammatory and immunosuppressive properties. This test helps confirm the presence of dexamethasone in serum, and is particularly useful for identifying the cause of secondary adrenal insufficiency. It is not, however, suitable as the sole basis for diagnosis or treatment decisions. Physicians rely on this test to assess exposure to dexamethasone, whether for therapeutic or surreptitious use, given its potential impact on clinical presentations such as Cushing syndrome with adrenal axis suppression.
Special Instructions
For optimal specimen collection, blood should be drawn between 7:30 a.m. and 9:00 a.m., following an evening dose of dexamethasone. It is important that serum be centrifuged and aliquoted into a plastic vial within one hour of collection and then frozen immediately to maintain specimen integrity. If not ordering electronically, completion and submission of the Therapeutics Test Request form (T831) are required.
Limitations
The presence of dexamethasone in serum indicates current or recent use; however, absence of detection does not completely rule out its use, as adrenal suppression may persist after the discontinuation of the steroid. Gross hemolysis, lipemia, and icterus are not causes for rejection, and therefore test performance is robust against these specimen conditions. Nonetheless, the interpretation of results should always consider the broader clinical context, including potential interfering substances and proper test selection.
New York Approved
Methodology
Mass Spectrometry (LC-MS/MS)
Biomarkers
LOINC Codes
- 14062-4
- 14062-4
Result Turnaround Time
2-10 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
0.6 mL
Container
Plastic vial
Collection Instructions
Draw blood between 7:30 a.m. and 9:00 a.m. following an evening dose. Centrifuge and aliquot serum into plastic vial within one hour of collection and freeze immediately.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 7 days |
| Frozen | 28 days |