Overnight dexamethasone suppression test: normal responses and the diagnosis of Cushing's syndrome.
Serum cortisol levels were measured the morning after the administration of 1 mg of dexamethasone. Only 5 of 190 subjects had serum cortisol levels greater than 2 micrograms/dL. Thus, the normal value after dexamethasone suppression is less than 2 micrograms/dL rather than less than 5 micrograms/dL as has generally been accepted. The distinction is important because some individuals with Cushing's syndrome partially suppress their cortisol levels to less than 5 but more than 2 micrograms/dL during the test procedure. Thus, the use of 5 micrograms/dL as the normal value may lead to an unnecessary delay in diagnosis.
Blethen
S L
SL
Department of Pediatrics, Schneider Children's Hospital, Long Island Jewish Medical Center, New Hyde Park, NY 10042.
Chasalow
F I
FI
D000293:Adolescent; D000303:Adrenal Cortex Diseases / Q000097:blood; D000328:Adult; D002648:Child; D003480:Cushing Syndrome / Q000175:diagnosis*; D003907:Dexamethasone; D005260:Female; D006628:Hirsutism / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D008599:Menstruation Disturbances / Q000097:blood; D009765:Obesity / Q000097:blood; D011863:Radioimmunoassay
D003907:Dexamethasone; D006854:Hydrocortisone