Evolving pregnancy screening options, such as noninvasive prenatal testing (NIPT), offer early genetic screening for chromosomal conditions using just one tube of blood—as early as 10 weeks into a pregnancy. Noninvasive testing provides high detection rates, low false-positive results, and no risk to mother and baby.
Other prenatal screening and diagnostic tests may require more than one office visit, multiple blood draws, or carry a higher risk of false-positive results.1-4 Diagnostic tests, such as chorionic villus sampling (CVS) or amniocentesis, provide definite results for most chromosome conditions but have an associated risk of miscarriage.
NIPT analyzes cell-free DNA from a maternal blood sample (mixture of fetal and maternal DNA) to screen for common chromosomal conditions including trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome).
The American Congress of Obstetricians and Gynecologists (ACOG) and International Society of Prenatal Diagnosis (ISPD), along with other professional societies, have stated that NIPT is an available screening option for all pregnant women.5,6
The NIPT workflow consists of several steps, and the complexity for each of these steps can vary widely between tests and the technical approach used. A typical workflow starts with isolating plasma from maternal blood draw. Cell-free DNA (cfDNA) is then extracted from plasma and prepared for analysis.
Data is generated from prepared cfDNA. Sophisticated analysis is then applied to the data.
Illumina NIPT uses whole-genome sequencing with next-generation sequencing (NGS) technology to analyze cfDNA fragments across the whole genome, which has proven advantages over other NIPT methodologies such as targeted sequencing and array-based methods. Test failure rates are substantially lower with whole-genome sequencing versus other methodologies.4, 7-9
With its high levels of sensitivity and accuracy, NGS produces the data quality needed for reliable analysis of the trace amounts of cfDNA found circulating within blood plasma.