dexamethasone suppression test


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dex·a·meth·a·sone sup·pres·sion test

a test for the detection and diagnosis of Cushing syndrome; following administration of 1.0 mg of dexamethasone at 11 p.m., normal people suppress plasma cortisol to low levels; patients with Cushing syndrome do not. Higher dose regimens distinguish between Cushing syndrome due to tumor and due to hyperplasia.

dexamethasone (DST) suppression test

a test of the blood or urine after administration of dexamethasone, a synthetic steroid similar to cortisol, that is used to diagnose Cushing's syndrome.

dexamethasone suppression test

Endocrinology A clinical test that measures the ability of dexamethasone to suppress ACTH and cortisol secretion by the adrenal gland. See Cushing's disease.

dexamethasone

a synthetic glucocorticoid used primarily as an anti-inflammatory agent in various conditions, including autoimmune diseases, hypersensitivity reactions and shock; it is also used in a screening test for the diagnosis of cushing's syndrome, and for the termination of pregnancy in cattle.

dexamethasone suppression test
the determination of blood cortisol levels before and after administration of dexamethasone assists in diagnosing Cushing's syndrome and identifying the cause, depending on the protocol and dose used. Dexamethasone suppresses pituitary secretion of ACTH in normal animals and therefore the blood level of cortisol is decreased; low doses do not suppress cortisol levels in dogs with pituitary-dependent Cushing's syndrome, high doses do. Cortisol production by functional adrenal tumors is not affected by dexamethasone.
References in periodicals archive ?
8 pg/dL after low-dose dexamethasone suppression test (LDDST) and radiological examination showed no adenomatous residue in the pituitary gland except for the former cystic lesion.
Diagnosis of Cushing's syndrome: reevaluation of midnight plasma cortisol vs urinary free cortisol and lowdose dexamethasone suppression test in a large patient group.
Plasma basal cortisol and ACTH levels, low-dose (1 mg) and highdose (8 or 16 mg) of dexamethasone suppression tests and 24-h UFC levels were measured.
Masses under 3 cm that show no evidence of rapid growth or hormonal change are not likely to become cancerous and should be monitored at yearly intervals with a dexamethasone suppression test.
Some medical centers recommend the 1-mg overnight dexamethasone suppression test followed by morning plasma cortisol measurement as the preferred screening test for Cushing syndrome.
For patients with masses less than 3 cm, the physician should do a 1-mg dexamethasone suppression test yearly.
In a patient of cushingoid appearance, a 24-hour urine cortisol test or low-dose dexamethasone suppression test is useful.
This is a consequence of enhanced negative feedback and increased glucocorticoid receptor sensitivity, which is evidenced by results of abnormal dexamethasone suppression tests.