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HelpTest Code AM-CORT* Dexamethasone Suppression Test
Synonyms/Keywords
Cortisol, AM
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Serum or Plasma | Serum Separator Tube (SST) | Red Top Tube (RTT), Lithium-heparin Plasma Separator Tube (PST), Sodium-heparin Green Top Tube (GTT) | 0.5 mL | 0.4 mL | 0.3 mL |
Collection/Processing Instructions
Indicate actual collection time on tube.
Separate cells within 30 minutes to minimize uptake of corticosteroids by RBC’s.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum/Plasma | Ambient | 8 hours |
| Refrigerated | 48 hours on gel | |
| Refrigerated | 7 days aliquoted | |
| Frozen | 7 days to 1 month |
Test Information
Add test comment "Dexamethasone Suppression Test" when requesting.
**See Dexamethasone Suppression Test for test protocol.
Interferences
Fluorescein will interfere; blood should not be drawn for 48 hours following fluorescein angiography for diabetic retinopathy.
Human Anti-Murine Antibodies (HAMA) may develop leading to test interference in patients receiving murine based chemotherapy agents or tumor-imaging studies.
For Tosoh AIA immunoassay method performed at Weston Lab, the drug asfotase alfa (Strensiq), used for the treatment of patients with perinatal/infantile- and juvenile-onset hypophosphatasia (HPP), causes falsely decreased test results. Test results from patients treated with asfotase alfa should be interpreted with respect to the clinical picture of the patient. Recommend sending test to Marshfield Center lab for analysis by an alternate method.
Interpretations
Values >10 ug/dL suggest Cushing’s Syndrome but may also be due to stress, failure to take dexamethasone, treatment with phenobarbital or phenytoin or endogenous depression.
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield | None |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Sunday | Less than 2 hours | Competitive Immunoassay using Direct Chemiluminescent Technology/Siemens Centaur |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 82533 |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | Cortisol Morning |