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

Abstract

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. Key words: K e y w o r d s] Prenatal diagnosis; Chromosome disorders; Down syndrome; Trisomy; Aneuploidy