9033例孕中期血清学筛查唐氏综合征模拟调整结果分析

摘要

目的 探讨降低唐氏综合征产前血清学筛查的筛查阳性率(SPR),提高血清学筛查临床效能的方法.方法 回顾性分析2013年4月-2014年4月9033例孕中期唐氏综合征血清学筛查的结果、各基础数据和方程曲线的变化情况,以本实验室数据为基准数据,对于重要调节参数进行模拟调整,结合产后随访结果评估孕中期血清学筛查唐氏综合征的准确性.结果 9033例孕妇孕中期血清学筛查的筛查阳性率为6.69％(604/9033),检出率(DR)为75％(3/4),假阳性率(FPR)为6.65％(601/9033).甲胎蛋白(AFP)的中位数倍数(MOM)值中位数偏低,SPR偏高;人绒毛膜促性腺激素游离β亚基(free hCGβ)MOM值中位数偏高,SPR偏高;游离雌三醇(uE3)MOM值中位数略微偏低,SPR略微偏高.综合三种因素,认为筛查阳性率处于偏高的状态.模拟调整AFP和free hCGβ的MOM值方程及体重校正方程,重新评估样本的风险值,高风险孕妇比率降为4.11％(371/9033),FPR降为4.07％(368/9033),并且按调整方程后的筛查结果经随访与原方程一致.结论 根据本实验室人群的数据进行本地化设置,定期对孕妇的AFP、free hCGβ、uE3的MOM值分布及体重进行校正,对降低唐氏综合征产前血清学筛查FPR具有重要意义.%Objective To reduce the screening positive rate (SPR) and improve clinical efficiency of maternal serum screening for Down's syndrome.Methods Nine thousand and thirty-three cases of second trimester maternal serum screening for Down's syndrome were included from Apr.2013 to Apr.2014 in the present study.The screening results,all basic data and equation curves were analyzed retrospectively.Based on the data from the authors' laboratory,the important adjustment parameters were simulated.Combined with postnatal follow-up results,the quality and clinical performance of second trimester serum screening for Down's syndrome were evaluated.Results The SPR of second trimester serum screening for Down's syndrome was 6.69％(604/9033),the detection rate (DR) was 75％(3/4),and FPR was 6.65％(601/9033).The median multiple of median (MOM) of alpha-fetoprotein (AFP) was low and SPR was high,and MOM of free human chorionic gonadotropin β subunit (free hCGβ) were high and SPR was high,while MOM of unconjugated estriol (uE3) were a little bit low,and SPR was slightly high.Considering these three factors,it is believed that the screening positive rate is high.By the simulation adjustments of MOM value equations (AFP and free hCGβ) and weight correction equation,the SPR reduced to 4.11％(371/9033) after recalculating the risk,FPR declined to 4.07％(368/9033),and no more Down's syndrome fetus were missed compared with postnatal follow-up results.Conclusion Based on a localized setting depending on the local laboratory data,we suggest that the MOM value distributions(AFP,free hCGβ and uE3) and maternal weight should be regularly adjusted since it is a useful way to reduce the false-positive rate and improve clinical efficiency of maternal serum screening for Down's syndrome.