Testing Laboratory
Auckland Te Toka Tumai | Auckland HospitalDepartment
Chemical Pathology
Delphic Registration Code (Alpha Code)
COR (Pre-dose)
DEXA (post-dose)
Test Code (Numeric Code)
3006
Laboratory Handling
Phlebotomy
Low Dose Overnight Dexamethazone Suppresion Test
Day 1
0900h: 5 mL blood. PST tube preferred. Request "Cortisol".
2300h:Give 1 mg dexamethasone, orally.
Day 2
0900h: 5 mL blood. PST tube preferred. Request "Post-dexamethasone cortisol".
Registration
Dexamethasone suppresion test - Cortisol.
Two separate numbers and test codes are to be used as these samples are timed:
Pre: COR / 3006
Post: DEXA / 3189
Internal ADHB samples:
ADHB DEXA (post dexamethasone suppression test cortisol) samples should also be registered for DEXT.
These samples can go onto the Cobas for Cortisol and then the aliquot put into the HPLC rack.
External Samples:
All other requests for Dexamethasone levels can just be registered for DEXT.
Sample Stability
See Cortisol (Blood)
Associated Tests
Synonyms
Plasma/Serum Dexamethasone suppression test, DST, Dex suppression test
Turnaround Time
1 day
Specimen Type
- Plasma
- Serum
Specimen Requirements
Tube/Container Type:
Preferred
- Lithium Heparin PST- Gel (Light Green Cap)
Acceptable
- EDTA (Lavender Cap)
- Lithium Heparin - Non-gel (Green Cap)
- Plain (Red Top)
- SST II (Gold Cap)
Preferred Sample Volume (ml)
5
Minimum Sample Volume (ml)
3.5
No of Samples Required
1
Paediatric Specimen Requirements
Tube/Container Type:
Preferred
- Lithium Heparin - Non-gel (Green Cap)
Acceptable
- Plain (Red Top)
Preferred Sample Volume (ml)
0.5
Minimum Sample Volume (ml)
0.5
Additional Specimen Information
0.5 mL Paediatric Microtainer PST Blood (Preferred)
0.5 mL Paediatric Microtainer Plain Blood
Last updated: 18/09/2026