The utility of measurements for detection of fetal Down syndrome.

The cutoff was set at 5% false positive rate by ROC curve analysis. To compare detection accuracies of factors, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at equivalent false positive rate. The number in parentheses indicates the 95% confidence interval.

通过受试者工作特征曲线（ROC curve）分析，将截断阈值设定为5%的假阳性率。为对比各因素的检测准确率，本研究在同等假阳性率条件下计算了灵敏度、阳性预测值（PPV）以及阴性预测值（NPV）。括号内的数值代表95%置信区间。