top of page

Cortisol Post Dexamethasone Suppression

Ordering Info & Methodology

Test Code

Cerner Synonyms


Cortisol Dexamethasone Suppression Test, Corticosteroids, Cortisol, Dexamethasone Suppression Test

Turn Around Time


Analyzed within 1 day of receipt.

Competitive immunoassay, electrochemiluminescence, Roche Cobas Cortisol II

Ordering Guide

Specimen Requirements

Sample Type

Collection Container

Alternate Collection Containers




0.5 mL

Add on stability
This is the length of time after sample collection that this analyte is stable. Test can be added to a previously collected sample if the time since collection is less than the add on stability time.

Minimum Volume

Add On Stability

Collection and Shipping Requirements

Refrigerate. Send on ice pack.

Reference Intervals

Female Reference Interval

Age Category
Reference Interval
≥ 0 y

Male Reference Interval

Age Category
Reference Interval
≥ 0 y
Additional Notes

[object Object]

Measurement Uncertainty (MU)
Every laboratory value is an estimate of the true concentration of substance. MU is the 95% confidence interval around that estimate. 95% of the time, the true concentration will be within the range of the reported value ±MU. This value is based on analytical variability (precision) and does not reflect other factors such as sample collection and handling which may also affect the result.


Reported sodium = 140 mmol/L
Sodium MU = 1%
Expanded uncertainty = 140 mmol/L ± 1% or 140mmol/L ± 1.4 mmol/L
Interpretation - the true value of sodium in the sample is in the range 138.6-141.4 mmol/L, with 95% confidence.


Measurement Uncertainty

Collect in morning following dexamethasone (1mg) given at 23:00 the evening prior. If dexamethasone not given, order random cortisol (CORT).

Exogenous estrogens can cause an apparent lack of suppression, and should be discontinued prior to testing.

Medications which alter dexamethasone metabolism can also affect result. Dexamethasone testing by mass spectrometry can be added on by request. 

bottom of page