Chromosomal abnormalities not currently detected by cell-free fetal DNA: a retrospective analysis at a single center

Current cell-free DNA testing could not detect up to one-half of the clinically significant chromosomal abnormalities that were found, which included clinically significant chromosomal microarray abnormalities. Among the 99 abnormal karyotypes that were not identified by cell-free DNA screening, 79% were from women with abnormal screening or abnormal ultrasound finding; 21% were from women who underwent invasive testing simply for advanced maternal age/concern, with no other risk factors or ultrasound findings. This information highlights the limitations of cell-free DNA screening and the importance of counseling patients about all prenatal screening and diagnostic procedures and about the added gain of invasive testing with karyotype and microarray.