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TEST ID DEXA Dexamethasone, Serum

Reporting Name

Dexamethasone, S

Specimen Type

Serum


Ordering Guidance


For synthetic glucocorticoid analyte screen, order SGSS / Synthetic Glucocorticoid Screen, Serum.



Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL serum

Collection Instructions:

1. Draw blood between 7:30 a.m. and 9:00 a.m. the morning following an evening dose.

2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial and freeze immediately. Do not send in original tube.

3. Send frozen.


Specimen Minimum Volume

Serum: 0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Frozen (preferred) 28 days
  Refrigerated  14 days
  Ambient  72 hours

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Reference Values

Baseline: <30 ng/dL

8:00 a.m. following 1 mg Dexamethasone, previous evening: >100 ng/dL

8:00 a.m. following 8 mg Dexamethasone, (4 x 2 mg doses) previous day: >800 ng/dL

Day(s) Performed

Tuesday, Thursday

Report Available

2 to 10 days

Specimen Retention Time

3 months

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

80299

Forms

If not ordering electronically, complete, print, and send a Therapeutics Test Request (T831) with the specimen.

Useful For

Measuring dexamethasone concentrations in serum

 

Ensuring that dexamethasone concentrations are adequate when performing dexamethasone suppression testing

 

Confirming the cause of secondary adrenal insufficiency

 

This test is not useful as the sole basis for diagnosis or treatment decisions.