Dexamethasone, Serum

Test Codes

EPIC: LAB1231936, Beaker: Dexameth, Quest: 29391

Department

Send Outs

Instructions

Specimen should be collected between 8 am – 10 am.

Specimen Collection Criteria

Collect: One plain Red-top tube. Gold-top SST unacceptable.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: 0.85 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.25 mL)

Rejection Criteria

• Gross hemolysis.
• Grossly lipemic.
• Serum separator tube (SST)
• Specimen not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and refrigerate (2-8°C or 36-46°F).

Transport: 0.85 mL serum, refrigerated (2-8°C or 36-46°F). (Minimum: 0.25 mL)

Storage

Specimen Stability for Testing:

Room temperature (20-26°C or 68-78°F): 72 hours
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Quest Diagnostics, Wood Dale, IL.

Performed

Monday.
Results available in 2-10 days.

Reference Range

Baseline:  Less than 20.0 ng/dL
1.0 mg dexamethasone overnight:  180-550 ng/dL (8:00 AM – 10:00 AM)

Test Methodology

Chromatography/Mass Spectrometry

Clinical Utility

Dexamethasone – Measurement of Dexamethasone is useful in assuring compliance with Dexamethasone treatment and documenting adequate dosing during such procedures as the Dexamethasone Suppression Test used in the differential diagnosis of Cushing's syndrome.

CPT Codes

80299
LOINC:  14062-4

Contacts

Last Updated

11/21/2025