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Laboratory Test Reference Guide

Laboratory Information

Test Name

Dexamethasone Suppression

Specimen Collection

Specimen Collection and Transport Protocols

Note that the Laboratory does not supply the dexamethasone. Refer to MDCU or pharmacy.

Adult Specimen

Heparin (light green), SST (gold)

Paediatric Specimen

0.4 ml Heparin (light green) or Plain serum (red)

Instructions for Referral to Waikato Lab

Aliquot Transport


Test Information



Test Availability

Mon - Fri, 0800 - 1630 excl. Public Holidays

Reference interval

An early morning cortisol level below 50 nmol/L  following a 1 mg Dexamethasone tablet taken at 2300 hrs the previous day excludes Cushing's syndrome.

Electronic Information

Registration Code

use the ISL Dynamic request form