Z. Barrou et al., OVERNIGHT DEXAMETHASONE SUPPRESSION TEST - COMPARISON OF PLASMA AND SALIVARY CORTISOL MEASUREMENT FOR THE SCREENING OF CUSHINGS-SYNDROME, European journal of endocrinology, 134(1), 1996, pp. 93-96
The overnight 1-mg dexamethasone suppression test is a very good scree
ning test for subjects suspected of having Gushing's syndrome. To simp
lify the procedure, we evaluated the 1-mg dexamethasone suppression te
st with measurement of salivary cortisol. We performed this test with
plasma and salivary cortisol measurements in 27 patients with Gushing'
s syndrome and 64 normal controls. The sensitivity and specificity of
plasma cortisol measurements were 100% and 87%, respectively, for a cu
t-off point of 100 nmol/l, in accordance with previous studies. The re
sults of salivary cortisol showed the absence of overlap between the t
wo groups, with a sensitivity and specificity of 100% for a cut-off po
int of 2.8 nmol/l. On a larger series, however, one might occasionally
miss the diagnosis of a patient with Gushing's syndrome. Therefore, w
e favor a cut-off point of 1.9 nmol/l, the sensitivity remaining at 10
0% and the specificity being 94%. In conclusion we recommend the overn
ight dexamethasone suppression test with measurement of salivary corti
sol as a screening test for Gushing's syndrome.