Dexamethasone Suppression Test

Specimen Required

2 Samples of 3-5 CC Clotted Blood or Serum

Fasting Required

Purpose of the Test

The Dexamethasone suppression test is primarily used to help diagnose Cushing’s syndrome, a condition caused by high levels of cortisol hormone in the body. This test is also used to differentiate between types of Cushing’s syndrome, such as adrenal or pituitary Cushing’s syndrome.

When this test is required

The test is requested when a person presents with symptoms of Cushing’s syndrome, or when a healthcare provider suspects the condition. It may also be ordered to monitor treatment for Cushing’s syndrome.

What the Test Detects

This test measures the levels of cortisol hormone in the blood before and after a person takes a dose of dexamethasone, a synthetic steroid medication. Dexamethasone is used to suppress the production of cortisol in the body, and if the body’s response is abnormal, it can indicate the presence of Cushing’s syndrome.

Preparation for the Test

Before the test, the patient will be required to stop taking any medications that can interfere with the results. This includes steroids, estrogen, and other medications that affect the adrenal gland. The patient should also fast for at least eight hours before the test.

Sample Requirements

The test requires a blood sample.

Additional Notes

The dexamethasone suppression test can have side effects, such as nausea, dizziness, and headache. The test is not recommended for pregnant women, people with a history of peptic ulcers, or those with a history of psychiatric disorders. The results of the test may be affected by certain medications, such as anticonvulsants and barbiturates, so it is important to inform the healthcare provider of any medications the patient is taking.

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