游离雌三醇在孕中期唐氏综合征筛查中的临床应用价值评估

Evaluation of Clinical Application of uE3 in Second-trimester Screening for Down＇s Syndrome with the Triple Test

目的探讨游离雌三醇（unconjugated estriol，uE3）在孕中期唐氏综合征（Down’s syndrome，DS）联合多指标筛查中的应用价值。方法用时间分辨荧光免疫法测定孕中期个体血清中的甲胎蛋白（AFP）、游离人类绒毛膜促性腺激素B亚单位（FhCG／3）及uE3水平，再采用随机配套的Wallac 2T专用DS风险分析软件进行数据分析，比较二联（AFP，FhCGS）和三联（AFP，F hCGβ和uE3）DS筛查的效果以评价uE3在DS筛查中的应用价值。结果通过对珠海市妇幼保健院2005年1月～2007年6月孕检的5781名孕中期的孕妇进行产前筛查，检出DS胎儿7例，漏诊1例，筛查人群中DS的发病率为1／723。以1：250作为阳性切值时，DS三联和二联筛查的筛查假阳性率分别为3．37％和7．70％，前者明显低于后者（Х^2=103．38，P〈0．005）；用两种筛查方案检出的DS阳性率分别为1．20‰和1．0‰，前者高于后者（Х^2=7．70，P〈0．01）。结论孕中期在DS二联筛查的基础上增加uE3指标，能更有效地筛查出DS。此对降低DS筛查的漏检率、减少创伤性的产前诊断都有着积极意义和实用价值。

Objective To evaluate the clinical application values of unconjugated estriol （uE3） in second-trimester screening for Down＇s syndrome （DS） with the triple test. Methods Alpha-fetoprotein （AFP）, free beta-human chorionic gonadotropin （F hCGβ） and uE3 levels in serum samples of second-trimester were measured by the time-resolved fluoroimmunoassay. The risk rate of DS was calculated by the Wallac Risks2T software. The positive detective rate（DR） and false positive rate（FPR） of DS with the triple and dual test were compared. Results From January 2005 to June 2007,5 781 pregnant women in second-trimester were screened and traced. Of the cases studied, 7 fetuses with DS were detected and 1 ease with DS was fail for screening. So,the incidence rate of DS was 1/723 in the second-trimester of Zhuhai city. When the risk of 1 in 250 as the cutoff to define a positive screening result of DS on the triple and the dual test, the FPR of the former（3. 37%） was significantly lower than the latter（7. 70%）（Х^2=103. 38, P〈0. 005）. The positive rates of detective which screened by the two methords were 1.2%0 and 1.0N0 ,the former higher than the latter（Х^2= 7.70,P〈0. 01）. Conclusion The triple test instead of the daul test for second-trimester screening for DS can be more effective. It is positive significance and practical value that reducing failure of detection for DS and avoiding wound prenatal diagnosis.