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Test Code FDXM Dexamethasone

Performing Laboratory

Esoterix Endocrinology

Specimen Type


Specimen Required

Draw blood in a plain, red-top tube(s). Separate serum within an hour. Spin down and send 3 mL of serum frozen in a plastic vial.


Note: Serum gel tube is acceptable, but must pour off into a plastic vial.

Specimen Minimum Volume

1 mL Note: Does not allow for repeat analysis.

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 365 days
  Refrigerated  14 days
  Ambient  6 days

Reference Values

Units = ng/dL


Adults baseline:                        <30

8:00 AM following 1 mg dexamethasone

previous evening:                      140 - 295

8:00 AM following 8 mg dexamethasone

(4 x 2 mg doses) previous day:  1600 - 2850

Day(s) and Time(s) Performed


CPT Code Information


Reject Due To

Hemolysis NA
Lipemia NA
Icterus NA
Other NA

Method Name

High-pressure liquid chromatography/tandem mass spectrometry (HPLC/MS-MS)

Secondary ID