利用受试者工作曲线确定^(14)C-尿素呼气试验的最佳临界值

Optimal cut-off determination of ^(14)C-urea breath test in diagnosis of Helicobacter pylori infection with ROC curve

目的利用受试者工作曲线(ROC)获得14C-尿素呼气试验(14C-UBT)的最佳临界值。方法收集来我院行胃镜检查和14C-UBT检查者124例,分别用快速尿素酶试验、病理Giemsa染色和14C-UBT测定Hp。快速尿素酶试验和病理结果相一致者入选,根据14C-UBT数值,绘制ROC曲线。结果14C-UBT的ROC曲线下面积为0.973(95%可信区间0.945~1.000)。最佳临界值为153 dpm/mmol CO2,此时灵敏度为0.90,特异度为0.97。当测定值超过150 dpm/mmol CO2后,阳性似然比显著提高。结论14C-UBT的最佳临界值为153 dpm/mmol CO2。

Objective To get the optimal cut-off of ^14C - urea breath test （^14C-UBT） in diagnosing Helicobacter pylori （Hp） infection. Methods H. pylori was detected by three methods, including rapid urinase test （RUT）, Giemsa staining and, ^14C - UBT in outpatients and inpatients undergoing gastroscopy in this hospital from March to September 2006. The diagnostic value of ^14C - UBT was analyzed in the patients with the same results by Giemsa staining and RUT. Based on ^14C-UBT values, ROC curves were drawn. Results The area under ROC of ^14C - UBT is 0. 973. The optimal cut-off in diagnosis of lip infection is 153 dpm/mmol CO2 with sensitivity of 0.90 and specificity of 0.97. Above. the level of this cut-off, the positive likelihood ratio rises significantly. Conclusions The optimal cut-off of ^14C - UBT in diagnosis of Hp infection is 153 dpm/mmol CO2.