The aim of the dexamethasone suppression test is to examine the functioning of the pituitary gland and adrenal cortex. In the test, the blood cortisol concentration is monitored after a dose of dexamethasone.

Dexamethasone is either prescribed or administered by the treatment unit requesting the test. The laboratory does not administer medication.

Medication influences the test result

In the week before the dexamethasone suppression test, you can use medication prescribed by your attending physician. Generally, this means medication prescribed by a specialist in internal medicine or a paediatrician.

Alcohol influences the test result

It is recommended to avoid alcohol for 24 hours before the test.

Stress influences the test result

Avoid physical exertion that causes sweating for 24 hours before the test.

Mental stress can also influence the test result. Inform the laboratory assistant taking your blood samples if you suffer from stress, depression, etc.


The treatment unit will give you instructions for taking the medication (dexamethasone pills) at 11 p.m. the night before the test. A blood sample will be taken on the following morning between 7 and 9 a.m. (preferably at 8 a.m.).

You must book an appointment for the blood sample collection.

Blood samples

The blood sample is taken between 7 and 9 a.m., preferably at 8 a.m.

Further information

For more information, please contact the customer service of Fimlab Laboratoriot Oy, tel. (03) 311 74445 on weekdays from 8 a.m. to 4 p.m., or the customer service of the Ostrobothnia region, tel. (06) 213 1626 on weekdays from 7 a.m. to 3 p.m.