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HealthInfo Canterbury

Dexamethasone suppression test

The dexamethasone suppression test gives your doctor valuable information about your cortisol production. Cortisol is a hormone produced by your adrenal glands.

Instructions

Contact the Endocrine Test Centre on (03) 364-0934 before you go for your dexamethasone suppression test. The Endocrine Test Centre is on the ground floor of the Christchurch outpatients building, 2 Oxford Terrace.

  1. Take the two 0.5 mg dexamethasone tablets as a single dose, as prescribed by your GP or specialist, between 11 pm and midnight. Take the tablets with or after food.

    If you have diabetes, dexamethasone may increase your blood sugar slightly for the next few days.

  2. Go to the Endocrine Tests Centre at 8 am the following morning for a blood test to assess your cortisol level.

    It is important that you go at 8 am, otherwise the test is not useful.

If you can't go to the Endocrine Test Centre, arrange to have a blood sample taken at your local laboratory or general practice. It is still important that the blood sample is taken at 8 am.

Written by the Hormone Measurement and Consultation Centre, Endocrine Department, Christchurch Hospital. Adapted by HealthInfo clinical advisers. Last reviewed March 2016. Last updated November 2018.

Page reference: 211674

Review key: HIHOT-213639