用孕妇体重校正唐氏筛查的血清标志物中位数倍数

Multiple of the median correction of Down＇s syndrome serum markers with pregnant body weight

目的应用孕妇体重对早、中孕期整合筛查唐氏综合征（DS）的血清标志物中位数倍数（MoM）进行校正，降低假阳性率。方法同一个孕妇分别于孕11～13周＋6d和15～20周＋6d用无菌真空采血管采取静脉血，采用时间分辨免疫荧光法（DELFIA）检测甲胎蛋白（AFP）、游离-β亚基-促绒毛膜性腺激素（Free—BhcG）、妊娠相关血浆蛋白A（PAPP—A）等3种血清标志物筛查指标，利用筛查风险评估软件，计算血清标志物的MoM，对7997例本地孕妇进行DS的风险评估，用非线性加权回归法，构建本地人群的体重方程，应用孕妇体重对本地人群的血清标志物MoM进行校正。比较校正前后各筛查指标MoM的变化情况，x2检验比较检出率和假阳性率。结果AFP、Free-βhCG、PAPP—A的MoM值随体重增加而减少，筛查指标MoM经体重方程校正后，人群筛查的假阳性率由4．12％减少到3．86％（x2=0．021，P〉0．05）。设定临界值（cut—off值）为1／270，本地人群体重方程校正前后检出率均为71．4％。结论孕妇体重对Ds筛查的结果有影响，为了得到精确的风险计算结果，筛查时建议建立、并用孕妇体重校正本地区血清标志物中位数倍数。

Objective With Pregnant women weight correction for serum marker Multiple of Median （MoM） of First trimester and second-trimester, integrated screen-ing for Down＇s syndrome （DS）, can reduce the false positive rate. Methods The same pregnant woman were taken venous blood vessels with sterile vacuum during the first trimester （ 11-13 W （ ＋ 6） d） and the second trimester （ 15-20 W （ ＋ 6） d）, Alpha-fetoprotein （AFP） , serum free beta-human chorionic gonadotrophin （Free beta hCG） and pregnancy- associated protein-A （PAPP-A） of three kinds of serum marker screening indicators were assayed by Using Time-resolved fluoroimmunoassay （TRFIA）. Screening for risk assessment software was used to calculate serum marker Multiple of Median, To assess the risks of 7 997 cases of local pregnant women DS, To construct the weight equation of local population using nonlinear weighted regression method, With maternal weight correction for serum marker Multiple of Median （MoM） of local pregnant women, Comparing the changes of screening index MoM before and after correction, chi square test to compare the detection rate and false positive rate. Results MoM values of three kinds of serum markers （ al-pha-fetoprotein, free beta subunit of human chorionic gonadotropin, pregnan-cy-associated plasma protein A） decreased with the weight increasing, Screening index MoM after correction weight equation, the screening of false positives for crowd from 4. 12% down to 3.86% （X2 =0. 021 ,P 〉0. 05）. Setting threshold （cut-off） at 1/270, and no change detection rates were 71.4% the local population before and after correction weight equation. Conclusion Maternal weight may affect the results of Down＇s syn-drome screening. When screening proposal to set up, it is worth making weight cor-rections for serum maker multiple of median in order to get accurate risk calculation results.