Fetal chromosome abnormalities, specifically aneuploidy, are a common cause of reproductive failure, congenital anomalies, developmental delay, and intellectual disabilities. Aneuploidy affects approximately 1 in 300 live births, with much higher rates associated with miscarriage and stillbirth. There are two types of prenatal tests for these disorders: diagnostic testing or screening. Diagnostic testing involves invasive procedures such as amniocentesis or chorionic villus sampling. These testing methods are considered the gold standard for detection of fetal aneuploidy. However, they are associated with a risk of pregnancy loss between 0.11% and 0.22%.

The VeriSeq NIPT Solution v2 is an in vitro diagnostic test intended for use as a screening test for the detection of fetal genetic anomalies from maternal peripheral whole blood specimens in pregnant women of at least 10 weeks gestation. This test is a screening test which does not replace diagnostic tests, e.g. fetal karyotyping. It uses whole genome sequencing to detect aneuploidy status of chromosomes.

A negative result does not fully exclude the possibility for the foetus to be affected. The Limit of Detection of the method is at a fetal fraction greater than or equal to 2% (Pertile et al., 2021 PMID: 34077512). If the fetal fraction is not sufficient or the data obtained do not allow a univocal interpretation, a new sample will be requested to repeat the analysis.

NIPT using whole-genome sequencing of cell-free DNA (cfDNA) can detect fetal aneuploidy for chromosomes 21, 18, 13 and the sex chromosomes with a high degree of accuracy. A recent meta-analysis of multiple clinical studies reported the weighted pooled detection rates and specificities for trisomy 21 and trisomy 18 in singleton pregnancies as follows: trisomy 21 99.7% and 99.96% and trisomy 18 97.9% and 99.96%, respectively. One study suggests that use of NIPT as a primary screen across all pregnancies could result in an 89% reduction in the number of confirmatory invasive procedures.

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