Test & Collection Guide

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Dexamethasone Suppression Test

Specimen types:
Container types:
Serum tube with gelSerum tube with gel
Collection Instructions:

The Dexamentasone Suppression Test (DST), also referred to as the "low dose DST" or "overnight DST", is a screening test for Cushing's Syndrome.

  • The requesting clinician should give the patient a 1mg dexamethasone tablet with instructions to take it at 11 pm. (for outpatients: the tablet should only be taken Sunday to Thursday evening, to ensure collection next day.)
  • The patient must present to the collection centre the following morning ( preferably before 10am ) and have a serum sample taken for cortisol analysis.

If there is any doubt do not send the patient away without documented consultation with a senior scientist. ( 9895 3548)

Endocrine consultation is suggested for "High Dose DST".

Reference Interval:
Cortisol <50nmol/L is considered normal and NOT consistent with Cushing's Syndrome.
Laboratory Use Only
Storage Instructions:
Endocrine consultation is suggested for "High Dose DST".