A Paradigm Shift: Considerations in Prenatal Cell-Free DNA Screening

Abstract

Background: Testing to determine the health of a fetus has undergone multiple iterations since the widespread adoption of amniocentesis in the 1970s, including several combinations of ultrasound and/or maternal serum screening. The clinical paradigm for prenatal screening for fetal chromosome aneuploidies was transformed by the introduction of cell-free DNA (cfDNA) screening or noninvasive prenatal screening in 2011. Content: The clinical performance of cfDNA screening is well-established for the most common autosomal and sex chromosome aneuploidies with a detection rate exceeding 90% for all aneuploidies. One of the most significant advantages of cfDNA screening relative to maternal serum screening is the markedly reduced false-positive rate, which is <0.5%. The clinical implementation of cfDNA screening is discussed at length, including key biological, preanalytical, and analytical factors that affect test performance. Summary: cfDNA prenatal screening for whole chromosome aneuploidies has become routine in high-risk obstetric populations. There is tremendous interest in expanding cfDNA screening to the general obstetric population. Early studies suggest that routine application of cfDNA screening is both feasible and effective, although significant economic and quality control considerations remain.