There are3 tests that can measure cortisol
Dexamethasone suppression test (DST): Measures your body’s response to an external source of cortisol called dexamethasone. This is done through a blood test
Late-night salivary cortisol (LNSC): Measures cortisol in the saliva when cortisol should be at its lowest level
Urinary free cortisol (UFC): Measures cortisol levels in the urine over a 24-hour period
A DST can help determine if you have an underlying condition called endogenous hypercortisolism
Sometimes, excess cortisol is made due to a growth on the adrenal gland, pituitary gland, or somewhere else in the body. A DST is the most sensitive way to tell if that is the case for you.
The DST in 1, 2, 3
Here’s some important information to know about the test:
Step 1
Your healthcare professional will prescribe a 1 mg dexamethasone tablet. This tablet should be taken between 11:00 PM and 12:00 AM.
Step 2
The following morning, you will need to have your blood drawn between 8:00 AM and 9:00 AM. The blood sample will then be sent to a lab.
Step 3
The lab will use your blood sample to test your cortisol level. The results will be sent to you and your healthcare professional. Be sure to discuss the results with your healthcare professional.
Before getting a DST, tell your healthcare professional about all medications you’re currently taking and any health issues you’re experiencing. These may affect your test results.
Where can I get a DST?
Ask a healthcare professional or search for a specialist near you.
Understandingyour DST results
If the results of your DST show that your cortisol is over 1.8 μg/dL, a condition called endogenous hypercortisolism could be the cause of your signs and symptoms. Your healthcare professional may need to run additional tests to confirm a diagnosis.
Talk to your healthcare professional about your results and appropriate next steps.
μg/dL = micrograms per deciliter. This is a common unit to use when measuring how much of a substance is in your blood.
Ready torequest a DST?
Fill out the Cortisol Self-Assessment to help you and a healthcare professional decide if getting a DST is the right next step.
