江苏省13041例无创产前检测的指征及结果分析

Clinical indications and detection efficiency of non-invasive prenatal testing in 13 041 cases from Jiangsu Province, China

目的：探讨江苏省无创产前检测（non-invasive prenatal testing，NIPT）的指征构成及检出结果。方法汇总2012年1月1日至2013年12月31日江苏省9所医疗机构的13041例NIPT检测结果，进行回顾性分析。所有病例均为单胎妊娠、自然受孕。NIPT检测范围包括13、18和21号染色体及性染色体非整倍体。对NIPT高风险孕妇，建议行介入性产前诊断及胎儿染色体核型分析。评估孕妇行NIPT的指征构成比和NIPT阳性预测值。结果13041例行NIPT的孕妇中，报告21、18、13-三体和X染色体数目异常高风险分别为88例（0.67%）、19例（0.15%）、9例（0.07%）和64例（0.49%），进一步行染色体核型分析的例数分别为74、13、8和44例，确诊为21、18、13-三体和X染色体数目异常的例数分别为67、12、1和18例，阳性预测值分别为90.5%（67/74）、12/13、1/8和40.9%（18/44）。1例孕妇血清学筛查提示18-三体高风险，但NIPT报告21-三体高风险，核型分析确诊为18-三体，引产胎盘的染色体核型分析为21和18-三体嵌合体。血清学筛查高风险为最常见NIPT指征，构成比为46.4%（6056/13041），其次为血清学筛查低风险但孕妇要求检测（28.9%，3773/13041）和高龄（20.5%，2673/13041）。结论江苏省孕妇行NIPT的主要指征为血清学筛查高风险、低风险但孕妇要求检测和高龄。NIPT对21-三体和18-三体具有较高的阳性预测值，但对13-三体和X染色体数目异常的阳性预测值较低。

Objective To determine the clinical indications and detection efficiency of non-invasive prenatal testing （NIPT） in Jiangsu Province, China. Methods A total of 13 041 pregnant women from nine hospitals in Jiangsu Province who voluntarily accepted NIPT for chromosome 13, 18, 21 and sex chromosome from January 1, 2012 to December 31, 2013 were analyzed retrospectively. All cases were singleton pregnancies and spontaneously conceived. Invasive prenatal diagnosis followed by fetal chromosome karyotype analysis was recommended in high-risk women following NIPT. The clinical indications and positive predictive value of NIPT were conducted. Results NIPT detected 88, 19, 9 and 64 cases at high risk for trisomy 21, trisomy 18, trisomy 13 and X chromosome aneuploidy, and the positive rate was 0.67%, 0.15%, 0.07% and 0.49%, respectively. Among the 74, 13, 8 and 44 high-risk cases who accepted chromosome karyotype analysis, respectively, 67 cases were diagnosed with trisomy 21, 12 cases with trisomy 18, one case with trisomy 13, and 18 cases with numerical X chromosome abnormality. The positive predictive value was 90.5% （67/74）, 12/13, 1/8 and 40.9% （18/44）, respectively. One pregnant woman who was reported as high-risk trisomy 21＆amp;nbsp;following NIPT, but high-risk trisomy 18 at prior serum screening, was eventually diagnosed with fetal trisomy 18 by chromosome karyotype analysis, whose placenta was a mosaic of trisomy 21 and trisomy 18. High-risk following serum screening was the most common indication for NIPT accounting for 46.4% （6 056/13 041）, followed by low-risk but asking for testing （28.9%, 3 773/13 041） and advanced age （20.5%, 2 673/13 041）. Conclusions High-risk, low-risk but asking for testing and advanced maternal age are common indications for NIPT in Jiangsu Province. The positive predictive value of NIPT for trisomy 21 or trisomy 18 is relatively high, but is much lower for trisomy 13 or X chromosome aneuploidy.