过夜小剂量地塞米松抑制试验对库欣综合征诊断价值的再探讨

目的重新探讨过夜小剂量地塞米松抑制试验对库欣综合征的诊断价值。方法回顾性分析我院1990年1月到2005年7月收治的52例库欣综合征患者和153例经住院检查排除库欣综合征的肥胖症和高血压病患者，比较过夜小剂量（1mg）地塞米松抑制试验的不同血清皮质醇切点对库欣综合征诊断的敏感性和特异性。结果在过夜1mg地塞米松抑制试验中，以试验当日晨8：00血清皮质醇为基础值，次日8：00血清皮质醇为基础值的50％以及次日晨8：00血清皮质醇275、200、138和50nmol／L为切点，诊断库欣综合征的敏感性分别为92．3％、92．3％、92．3％、92．3％和100．0％，特异性分别为90．8％、98．7％、96．1％、91．5％和78．4％。结论在过夜1mg地塞米松抑制试验中，以次日晨8：00血清皮质醇50nmol／L为切点具有较高的敏感性，可作为库欣综合征的第一线筛选试验。

Re-evaluation of overnight low-dose dexamethasone suppression test in the diagnosis of Cushing syndrome

Objective To reinvestigate the value of overnight low-dose dexamethasone suppression test in the diagnosis of Cushing syndrome.Methods Fifty-two patients with Cushing syndrome and 153 patients with simple obesity or essential hypertension in whom Cushing syndrome was excluded were studied retrospectively in order to compare the sensitivity and specificity of different serum cortisol cut-off levels in overnight 1 mg dexamethasone suppression test in the diagnosis of Cushing syndrome.Results The sensitivity of 50% of basal serum cortisol level at 8:00 and of the serum cortisol cut-off levels of 275,200,138,50 nmoL/L at 8:00 after the overnight 1 mg dexamethasone suppression test was 92.3%,92.3%,92.3%,92.3% and 100.0% respectively, and the specificity was 90.8%,98.7%,96.1%,91.5% and 78.4%,respectively.Conclusion The serum cortisol cut-off level of 50 nmol/L in the overnight 1 mg dexamethasone suppression test has very high sensitivity and can be used as a screening test for Cushing syndrome.