Dexamethasone Supression Test

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Testing Laboratory

Waitematā | Northshore Hospital

Department

Chemical Pathology

Delphic Registration Code (Alpha Code)

MCOR

Test Code (Numeric Code)

0377

Laboratory Handling

Registration

Registration Codes: Pre-dexamethasone = MCOR, Post-dexamethasone = MDEX

Sample Stability

24 hours

Associated Tests

Synonyms

Dexamethasone

Turnaround Time

2 hours

Specimen Type

  • Plasma
  • Serum

Specimen Requirements

Tube/Container Type:

Preferred
  • Lithium Heparin - Non-gel (Green Cap)
Preferred if Waitākere
  • SST II (Gold Cap)
Acceptable
  • Plain (Red Top)
  • SST II (Gold Cap)
Preferred Sample Volume (ml)

4

Minimum Sample Volume (ml)

1

Paediatric Specimen Requirements

Tube/Container Type:

Preferred
  • Heparin (Microtainer)
Acceptable
  • Plain(Microtainer)
  • SST(Microtainer)
Minimum Sample Volume (ml)

0.4

Additional Specimen Information

Day 1:
0900 hrs - take 4 ml blood in plain or heparin tube.
2300 hrs - give 1 mg dexamethasone, orally.
Day 2:
0900 hrs - take 4 ml blood in plain or heparin tube
Request cortisol on Day 1 specimen and Dexamethasone Suppression test on Day 2 specimen

Last updated: 19/12/2025