三种库欣综合征筛查试验诊断切点的选择及筛查价值的比较  

Comparing Overnight Dexamethasone Suppression Test,Urine Free Cortisol,and Midnight Serum Cortisol for the Initial Diagnosis of Cushing's Syndrome

作　　者：唐天娇 刘玉平[1] 余叶蓉[1] 

机构地区：[1]四川大学华西医院内分泌代谢科,成都610041

出　　处：《四川大学学报（医学版）》2013年第5期764-768,共5页Journal of Sichuan University(Medical Sciences)

摘　　要：目的根据美国及欧洲内分泌协会2008年库欣综合征诊断指南,比较午夜血皮质醇(PTC-24h)、口服1mg地塞米松过夜抑制试验(PTC-DST)以及24h尿游离皮质醇(UFC)筛查库欣综合征的准确性,并探讨其诊断切点是否适用于中国人群。方法回顾性分析102例库欣综合征患者以及102例单纯性肥胖、多囊卵巢综合征、肾上腺结节患者和正常健康人的PTC-DST、UFC、PTC-24h监测结果,采用相关操作特征曲线(ROC曲线)分析其筛查库欣综合征的敏感性(Se)和特异性(Sp)。结果 ROC曲线显示,当PTC-DST以86nmol/L为切点时其诊断价值最高(Se 98.7%,Sp 97.2%),当切点取为60nmol/L时,Se 100%,Sp 95.8%,当切点取为50nmol/L时,Se 100%,Sp 94.4%。UFC的ROC曲线上最接近1的切点为230.15μg/24h(Se 92.2%,Sp 95.7%),当切点取为127.55μg/24h时,Se 96.1%,Sp 85.1%。PTC-24h的ROC曲线上最接近1的切点为347nmol/L(Se 93.4%,Sp98.4%),当切点取为207nmol/L时,Se 98.9%,Sp 85.2%。ROC曲线下面积PTC-DST与PTC-24h差异无统计学意义,两者均大于UFC(P<0.05)。结论相比美国及欧洲内分泌协会于2008年颁布的库欣综合征指南建议的以50nmol/L为PTC-DST的切点,60nmol/L对中国人群来说敏感性不变,诊断特异性更高。UFC以本实验室参考值上界即127.55μg/24h为切点、PTC-24h以207nmol/L为切点均具有较高的筛查价值。PTC-DST与PTC-24h筛查库欣综合征的价值基本一致,且均高于UFC。从实用性角度看,门诊库欣综合征患者的筛查选用PTC-DST最适合。Objective To identify retrospectively the optimal cut-off points and the values of overnight dexamethasone suppression test,urine free cortisol,and midnight serum cortisol in the initial diagnosis of Cushing's syndrome in Chinese people.Methods The results of overnight low-dose dexamethasone suppression test(PTCDST),urine free cortisol(UFC)and late-night plasma total cortisol(PTC-24h)of 102 patients who had clinically confirmed Cushing's syndrome and 102 patients without Cushing's syndrome were extracted from West China Hospital.Receiver operating characteristic(ROC)curves were drawn to identify optimal cut-off points of the three assays and their values in diagnosing Cushing's syndrome.Results The optimal cut-off point(the point on the ROC curve closest to 1)for PTC-DST was set at 86nmol/L,with 98.7% sensitivity and 97.2% specificity(100% sensitivity and 94.4% specificity was achieved at 50nmol/L;100%sensitivity and 95.8% specificity was achieved at 60nmol/L).The optimal cut-off point for PTC-24hwas set at 347nmol/L,with 93.4% sensitivity and 98.4%specificity(98.9%sensitivity and 85.2% specificity was achieved at 207nmol/L).The optimal cut-off point for UFC was set at 230.15μg/24h,with 92.2 sensitivity and 95.7% specificity(96.1% sensitivity and 85.1% specificity was achieved at 127.55μg/24h).There was no significant difference between PTC-DST and PTC-24h in the areas under the ROC curves,whereas both had a greater area under the ROC curve than that of UFC(P<0.05).Conclusion Compared with the recommended 50nmol/L cut-off point for PTC-DST in the USA and the European countries,the same sensitivity and a higher specificity can be achieved at a cut-off at 60nmol/L for the Chinese people.PTC-DST and PTC-24h have similar values in the initial diagnosis of Cushing's syndrome,but PTC-DST is more convenient to be used in outpatient environment.

关 键 词：库欣综合征 地塞米松过夜抑制试验 尿游离皮质醇 午夜血皮质醇 切点 

分 类 号：R586.2[医药卫生—内分泌]