BGI Diagnostics publishes world’s largest study tracking the clinical performance of NIPT in nearly 150,000 pregnancies
The data, published in the journal Ultrasound Obstetrics and Gynecology, demonstrate that the performance metrics of previously published studies from both BGI and other NIPT providers, hold true in the context of a dramatically expanded group of clinical samples.
Wang Wei, the study’s first author and medical director of BGI Diagnostics, notes ‘previous validations have been done in small and well-controlled cohorts…In this paper we showed the first hand information of NIPT performance in a very large population, and consistency with the accuracy shown in small studies. The results also suggest that high quality of NIPT service can be achieved at NGS based clinical labs with strict protocols and standards.’
The study reported on 146,958 samples from 508 medical centres in mainland China. Testing was carried out between early 2012 and mid-2013 for trisomy 21, 18 and 13.
The sensitivity for trisomy 21, 18 and 13 was caluclated as 99.1 percent, 98.2 percent and 100 percent in the three trisomies respectively. Specificity was about 99.95 percent in each case. For trisomy 21 and trisomy 18, the false positive rate was 0.05 percent and for trisomy 13 it was 0.04 percent.
- The study shows that the NIFTY test’s performance does not differ substantially among higher and lower risk women. Wang Wei: ‘Our data provided so far the largest and most comprehensive evidence of NIPT performance in low-risk pregnant women, which strongly supports the use of NIPT in the general population for screening of T21, T18 and T13.’
- Low fetal fraction was not a major contributor to NIPT misdiagnoses. This is significant as Wang Wei notes the importance of fetal fraction has been ‘overwhelmingly emphasized in the past few years, and low fetal fraction is believed to be a major risk of causing NIPT false results.’
Noninvasive Prenatal Testing for Trisomy 21, 18 and 13 – Clinical Experience from 146,958 Pregnancies, Hongyun Zhang, Ya Gao, Fuman Jiang, Meili Fu, Yuying Yuan, Yulai Guo, Zhongyi Zhu, Mengmeng Lin, Qiufang Liu, Zhongming Tian, Haiquan Zhang, Fang Chen, Tze Kin Lau, Lijian Zhao, Xin Yi, Ye Yin and Wei Wang, Ultrasound in Obstetrics & Gynecology, DOI: 10.1002/uog.14792, published online 19 January 2015.
Source: BGI Diagnostics