Dexamethasone suppression test

Dexamethasone Suppression Test (DST)

The Dexamethasone Suppression Test (DST) is a medical diagnostic test used to assess adrenal gland function by observing how cortisol levels in the blood change in response to oral doses or an injection of dexamethasone, a synthetic steroid.

Procedure

During the DST, a patient is given a dose of dexamethasone, and cortisol levels are measured at specific intervals thereafter. The test can be conducted in different forms, such as the standard DST and the overnight DST.

Clinical Use

The primary use of the DST is in the diagnosis of Cushing's syndrome, a condition characterized by excessive cortisol production. The test helps determine whether the high cortisol levels are due to Cushing's syndrome or other factors.

Diagnostic Criteria

For Cushing's syndrome, a failure to adequately suppress serum cortisol levels after dexamethasone administration is indicative of the disorder.

Limitations

While useful for diagnosing Cushing's syndrome, the DST has limitations. It can produce false-positive results in patients with conditions like depression, obesity, or high physical stress.

Historical Context

Historically, the DST was used in diagnosing depression. By 1988, however, it was recognized that its clinical utility for diagnosing depression was severely limited, and it is no longer routinely used for this purpose.

External Links

• Mayo Clinic - Dexamethasone Suppression Test
• MedlinePlus - Dexamethasone Suppression Test

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