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HelpTest Code LAB4061 DEXAMETHASONE SUPPRESSION TEST
Specimen Type
Preferred Sample: Serum (SST, Gold, Corvac, Tiger, Red Top Tube)
Alternate Sample: Lithium Heparin Plasma (PST, Mint Green Tube)
Collection Instructions
Low Dose: Draw cortisols at 8:00 am the morning before and the morning after an 11:00 pm oral dose of 1.0 mg dexamethasone.
High Dose: Draw cortisols at 8:00 am the morning before and the morning after an 11:00 pm oral dose of 8.0 mg dexamethasone.
See also:
Specimen Volume
1 mL for each timed sample
Minimum Volume
0.2 mL for each timed sample
Turnaround Time
STAT: 1 hour
Routine: 4 hours
Times are after each specimen is drawn
Test Schedule
Daily
Sample Stability
Room Temp: 24 hours
Refrigerated: 4 days
Specimen Processing
Spin completely clotted SST tube for 10 minutes. Store tubes in refrigerator until testing can be done.
Method
Chemiluminescent microparticle immunoassay (CMIA)
Reference Ranges
Cortisol Pre-Suppression ug/dL 4.3-22.4
Cortisol Post-Suppression ug/dL
Normal patients suppress their cortisol levels to LT 5.0 ug/dL
Critical Value: None
Reportable Limit: 0.1 - 634.0
Reporting Limit
Measuring Range: 0.1 - 63.4 ug/dL
Reporting Range: 0.1 -634.0 ug/dL (Manual Dilution 1:10 with Diluent Universal 2)
Synonyms
Cortisol Suppression (2 samples)
Test Components
Cortisol Pre-Suppression, ug/dL; Date/Time Collected; Cortisol Post-Suppression, ug/dL; Date/Time Collected.
CPT Codes
82533 × 2
Notes
Low dose dexamethasone usually does not suppress cortisol production in Cushing's Syndrome.