Dexamethasone (Referred Test)

Diagnostic Use

Requests for Dexamethasone level are referred to LabPlus, Auckland.

Dexamethasone levels may be useful in the interpretation of cortisol levels after dexamethasone suppression test if cortisol is not adequately suppressed i.e. non-compliance or malabsorption.

Department

Endocrinology Lab

Delphic Registration Code

ENDO

Laboratory Handling

Phlebotomy

Please label with collection time.

Registration

NOT the same as Dexamethasone Suppression Test - see individual page.

Separating

Separate and send at 2-8C to LabPlus, Auckland.

Turnaround Time

14 days

Specimen Type

• Serum
• Plasma

Specimen Requirements

Tube/Container Type:

Preferred

• Serum (Red Cap)
• SST II (Gold Cap)
• Lithium Heparin - Non-gel (Green Cap)
• Lithium Heparin - Gel (Light Green Cap)

Preferred if West Coast

• SST II (Gold Cap)
• Lithium Heparin - Gel (Light Green Cap)

Acceptable

• SST II (Gold Cap)
• Lithium Heparin - Gel (Light Green Cap)

Preferred Sample Volume (ml)

3.5

Aliquot Instructions

Sample Type

• Serum
• Plasma

Transport to Lab

Chilled (2 - 8 degrees Celsius)

Additional Referral/Aliquot Information

Send 2-8C to LabPlus Auckland.

Interpretation

In the setting of 1 mg overnight dexamethasone suppression test, the LabPlus in-house evaluation suggests that a dexamethasone level <3.1nmol/L from the plasma sample collected the next morning (8-10am) may not be sufficient to cause full suppression of morning cortisol to below 50nmol/L in some healthy individuals.

Test Method

LCMS/MS

Contact Canterbury Health Laboratories on +64 3 364 0484 or email LabInfo@cdhb.health.nz

Contact Information

Enquiry Form

Contact Information

Enquiry Form