Category: Genetics
Poster Session I
The goal of this study was to determine the likelihood of obtaining an aneuploidy assessment by single nucleotide polymorphism-based non-invasive prenatal testing (SNP-NIPT) upon redraw after an initial no-call using an updated SNP-based algorithm, which includes a deep neural network and artificial intelligence.
Study Design:
We performed a retrospective analysis of NIPT cases from April 2021 to December 2021 that had an initial no-call and a second sample analyzed. Cases with suspected low fetal fraction (FF) due to aneuploidy were excluded. Singleton, monozygotic (MZ) twins, and dizygotic (DZ) twins were analyzed separately.
Results:
During the 8-month study period, there was an overall no-call rate of 2.56%. A total of 7,321 singleton cases had an initial no-call and were not considered to be at elevated risk due to unusually low FF and a second sample drawn (Figure 1). A low number of MZ twin samples (n=228) had an initial no-call with a second blood draw. Results were similar to singletons. 750 DZ twins had an initial no-call and had a second blood draw (Figure 2). The lower of the two FF was used in the analysis. For cases with an initial no-call without FF data, a similar trend of lower maternal weight (MW) correlated to obtaining a result. For women in all MW categories having both singleton and DZ pregnancies with an initial FF >2.4%, there was a >50% likelihood of obtaining a result with a repeat blood draw. For women with a MW of < 240 lbs and a singleton pregnancy with an FF >2.0%, the likelihood of obtaining a result with a repeat blood draw was also >50%.
Conclusion:
For all pregnancy types (singleton, MZ and DZ twins), a higher initial FF and lower MW were associated with a higher likelihood of obtaining a fetal result from a second sample. For SNP-NIPT cases requiring a redraw, this pregnancy-specific data can help clinicians counsel patients about the likelihood of receiving results with a second blood draw.
Manesha Putra, MD (he/him/his)
University of Colorado Anschutz Medical Campus
Aurora, Colorado, United States
Katie Plunkett, MS
Natera, Inc.
Austin, Texas, United States
Yuhang Liu, PhD
Natera, Inc.
Austin, Texas, United States
Felipe Acosta, PhD
Natera, Inc.
Austin, Texas, United States
Lauren Grimes, MS
Natera, Inc.
Austin, Texas, United States
Wenbo Xu, MD, PhD
Natera, Inc.
San Carlos, California, United States
Russel Jelsema, MD
Natera
San Carlos, California, United States
Melissa Maisenbacher, BS, MS (she/her/hers)
Director
Natera
San Carlos, California, United States