Analysis of cell-free DNA in a consecutive series of 13,607 routine cases for the detection of fetal chromosomal aneuploidies in a single center in Germany.

Purpose: Noninvasive prenatal testing (NIPT) is a highly sensitive and specific method for detection of fetal chromosomal aneuploidies from maternal plasma. The objective of this study was to determine the performance of a new paired-end sequencing-based NIPT assay in 13,607 pregnancies from a single center in Germany.

Methods: Samples from 13,607 pregnant women who previously underwent NIPT were analyzed using VeriSeq NIPT Solution v2 assay for presence of common fetal trisomies and monosomy X. Follow-up to determine clinical truth was carried out.

Results: Of the 13,607 cases, 13,509 received a NIPT call resulting in a low study failure rate of 0.72%. There were 188 (1.4%) high-risk calls: 117 trisomy 21, 34 trisomy 18, 23 trisomy 13, one trisomy 21 + 13, and 13 monosomy X. High sensitivities and specificities of ≥ 98.89% were reported for all four aneuploidy conditions. Of the high-risk cases, clinical follow-up data were available for 77.1% (145/188). Clinical follow-up of high-risk calls revealed an overall positive predictive value of 84.8% (potential range 65.4-88.3%). NIPT results were provided for samples across a range of fetal fractions, down to 2% fetal fraction.

Conclusion: The VeriSeq NIPT Solution v2 assay detected fetal chromosomal aneuploidies across a range of fetal fractions with high sensitivities and specificities observed based on known clinical outcomes, a high overall PPV, and a low failure rate.