Abstract：
OBJECTIVE: The aim of this work was to compare different local cutoff values (LCV) and inline cutoff values (ICV) in pregnant women in the second trimester at high risk for carrying fetuses with trisomy 21.
METHODS: This retrospective cohort study analyzed prenatal screening outcomes in pregnant women (n = 311,561). The receiver operating characteristic curve was used to evaluate the diagnostic significance of the trisomy 21 risk value, alpha-fetoprotein, and free beta human chorionic gonadotropin multiple of the median for predicting trisomy 21 risk. The cutoff value corresponding to the maximal Youden index was taken as the LCV. The screening efficiency of both cutoff values was compared.
RESULTS: The LCV cutoff value was lower than the ICV cutoff value (1/643 vs 1/270). The sensitivity increased by 19.80%, the positive predictive value decreased by 0.20%, and the false-positive rate increased by 6.50%.
CONCLUSIONS: The LCV should be used to determine trisomy 21 risk, which can increase the detection rate of trisomy 21 in the second trimester.
METHODS: This retrospective cohort study analyzed prenatal screening outcomes in pregnant women (n = 311,561). The receiver operating characteristic curve was used to evaluate the diagnostic significance of the trisomy 21 risk value, alpha-fetoprotein, and free beta human chorionic gonadotropin multiple of the median for predicting trisomy 21 risk. The cutoff value corresponding to the maximal Youden index was taken as the LCV. The screening efficiency of both cutoff values was compared.
RESULTS: The LCV cutoff value was lower than the ICV cutoff value (1/643 vs 1/270). The sensitivity increased by 19.80%, the positive predictive value decreased by 0.20%, and the false-positive rate increased by 6.50%.
CONCLUSIONS: The LCV should be used to determine trisomy 21 risk, which can increase the detection rate of trisomy 21 in the second trimester.
摘要：
目的：这项工作的目的是比较妊娠中期孕妇的不同局部截断值（LCV）和内联截断值（ICV），这些孕妇具有携带21三体胎儿的高风险。
方法：这项回顾性队列研究分析了孕妇的产前筛查结果（n=311,561）。受试者工作特征曲线用于评估21三体风险值的诊断意义，甲胎蛋白,和游离β人绒毛膜促性腺激素的中位数倍数预测21三体病风险。将对应于最大Youden指数的截止值作为LCV。比较两个截止值的筛选效率。
结果：LCV截止值低于ICV截止值（1/643对1/270）。灵敏度提高了19.80%，阳性预测值下降了0.20%，假阳性率增加了6.50%。
结论：应使用LCV来确定21三体的风险，可以提高孕中期21三体的检出率。
方法：这项回顾性队列研究分析了孕妇的产前筛查结果（n=311,561）。受试者工作特征曲线用于评估21三体风险值的诊断意义，甲胎蛋白,和游离β人绒毛膜促性腺激素的中位数倍数预测21三体病风险。将对应于最大Youden指数的截止值作为LCV。比较两个截止值的筛选效率。
结果：LCV截止值低于ICV截止值（1/643对1/270）。灵敏度提高了19.80%，阳性预测值下降了0.20%，假阳性率增加了6.50%。
结论：应使用LCV来确定21三体的风险，可以提高孕中期21三体的检出率。
