胎儿颈项透明层厚度联合血清学检测在唐氏综合征筛查中的应用

目的:探讨孕早期颈项透明层厚度(NT)联合孕中期母体血清甲胎蛋白(AFP)、游离雌三醇(uE3)及绒毛膜促性腺激素(β-HCG)三项生化指标在唐氏综合征筛查中的意义和作用。方法:对2009年8月～2012年2月唐山地区自愿接受产前唐氏综合征筛查并住院分娩和随访的孕妇共4 029例,在妊娠11～14周B超检测胎儿颈项透明层厚度,NT≥2.5 mm为高风险。在妊娠15～21周检测母体血清标志物甲胎蛋白(AFP)、游离雌三醇(uE3)和绒毛膜促性腺激素(β-HCG),利用唐氏综合征专用风险评估软件,结合孕妇体重、年龄、孕周进行风险评估,妊娠中期接受唐氏综合征筛查的孕妇其合并危险度>1/270,即视作阳性。对高危险度孕妇进行遗传咨询,在知情同意的情况下行羊水穿刺,进行染色体检查确诊。对单用NT或血清三联筛查与二者联合筛查结果进行比较。结果:分别用NT、血清三联筛查两种方法检测结果比较差异无统计学意义;两种方法单一阳性即视为阳性的联合应用灵敏度增高,漏诊率降低,但特异度也降低,阳性预测值最低;两种方法均阳性才视为阳性的联合应用灵敏度降低,漏诊率增高,但特异度也增高,阳性预测值最高;结论:NT、血清三联筛查两种方法不能互相取代,两者任一阳性联合可以提高患者的检出比例,降低漏诊率;两者均为阳性联合分析可以增加阴性的排除能力,可使有创性诊断羊水穿刺更有针对性。

Application of thickness of fetal nuchal translucency combined with serological test in screening of Down's syndrome

Objective To explore the significances and effects of thickness of fetal nuchal translucency(NT) during the first trimester of pregnancy combined with joint detection of maternal serum alpha-fetoprotein(AFP),uncojugated estriol(uE3),and β-human chorionic gonadotropin(β-HCG) in screening of Down's syndrome.Methods A total of 4 029 pregnant women who voluntarily received prenatal Down's syndrome screening and gave birth to their babies and in Tangshan area from August 2009 to February 2012 were selected,the chickness of NT was detected at 11-14 gestational weeks by ultrasound,NT≥2.5 mm was designed as high risk;the levels of maternal serum AFP,uE3,and β-HCG were detected at 15-21 gestational weeks,combing with maternal body weight,age,and gestational week,a special risk assessment software of Down's syndrome was used to conduct risk assessment;the combined risk degree more than 1/270 was designed as positive among the pregnant women receiving Down's syndrome during the second trimester of pregnancy;the high risk pregnant women received genetic consultation,in the case of informed consent,amniocentesis was performed,chromosomal examination was conducted to diagnose definitely;the screening results of single NT or serological test and joint detection were compared.Results There was no statistically significant difference in detection result between NT screening and serological test;if one detection result was positive,the sensitivity of joint detection of NT screening and serological test increased,the rate of missed diagnosis reduced,but the specificity also decreased,the positive predictive value was the lowest;if two detection results were positive,the sensitivity of joint detection of NT screening and serological test decreased,the rate of missed diagnosis increased,but the specificity also increased,the positive predictive value was the highest.Conclusion NT screening and serological triple test can't replace each other,if one detection result is positive,joint detection of NT and serological test can improve the detection rate of positive patients,reduce the missed diagnostic rate;if two detection results are positive,joint detection can enhance the exclusive ability of negative patients,and improve the pertinence of invasive amniocentesis.