Comparison of various assays in diagnosing Cushing′s syndrome
- VernacularTitle:诊断库欣综合征时多种检查方法的比较
- Author:
Wei ZHANG
;
Zhengyi TANG
;
Fang HUANG
;
Weiqing WANG
;
Yi ZHANG
;
Xiaoying LI
;
Yongju ZHAO
;
Renming HU
;
Guang NING
- Publication Type:Journal Article
- Keywords:
Cushing syndrome;
Dexamethasone suppression test
- From:
Chinese Journal of Endocrinology and Metabolism
2001;0(05):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the sensitivity and specificity of various assays in diagnosing Cushing′s syndrome. Methods The plasma cortisol, urinary free cortisol (UFC), circadian rhythm in cortisol secretion and dexamethasone suppression test were assessed in 173 patients clinically diagnosed Cushing′s syndrome. The data were compared with the postoperative pathologic diagnosis. Results The normal diurnal rhythm of cortisol secretion was lost in 92.9% patients with Cushing′s syndrome. The loss of normal diurnal rhythm of cortisol secretion of 2 time points occurred in 85.1% (8:00, 16:00) and 91.8% (8:00, 24:00), and that of 3 time points (8:00, 16:00, 24:00) in 94.7% of the cases. The excretion of UFC was increased in 91.7% of patients with Cushing′s syndrome. Low-dosedexamethasonedidnotsuppressthe excessive secretion of glucocorticoid in 79.7% (1 mg) and 84.3% (2 mg) patients with Cushing′s syndrome. The basal level of plasma cortisol was raised in 75.6% patients. The sensitivity of 8 mg dexamethasone suppression test was 50%-70% as the standard was set at 50% suppression, and specificity was more than 95%. Conclusion The most sensitive tests for Cushing′s syndrome are the loss of normal circadian rhythm of cortisol secretion and increased UFC. The method of 3 time points is more sensitive than that of 2 time points in the assessment of circadian rhythm. The 8 mg dexamethasone suppression test is the most useful method in differentiating Cushing′s disease from adrenal adenoma.
