Dexamethasone [29391X]

Test Code
29391

CPT Codes
80299

Preferred Specimen
0.85 mL serum collected in a red-top tube (no gel)

Minimum Volume
Serum 0.25 mL • Plasma 0.6 mL

Other Acceptable Specimens
Plasma collected in: Sodium heparin (green-top), lithium heparin (green-top) or sodium fluoride (gray-top) tube

Instructions
Draw specimen between 8:00 a.m. and 10:00 a.m.

Transport Container
Plastic screw-cap vial

Transport Temperature
Refrigerated (cold packs)

Specimen Stability
Room temperature: 24 hours
Refrigerated: 7 days
Frozen: 2 years

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Serum Separator Tubes (SST®) • Received room temperature • Moderate hemolysis

Methodology
Chromatography/Mass Spectrometry

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Mon; Report available: 3-11 days

Reference Range
Baseline: Less than 20 ng/dL
1 mg dexamethasone overnight: 180-550 ng/dL (8:00-10:00 AM)

Clinical Significance
Test used in the differential diagnosis of Cushing's syndrome.

Performing Laboratory
Quest Diagnostics Nichols Institute San Juan Capistrano
33608 Ortega Highway
San Juan Capistrano, CA 92675



The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.