Noninvasive prenatal testing by cell-free DNA: Technology, biology, clinical utility, and limitations

The introduction of cell-free DNA testing has had a substantial impact on prenatal screening and diagnosis paradigms over the last half decade. There are several approaches to cell-free DNA analysis that rely on next-generation sequencing or microarray technology, targeted or genome-wide. There are also several biological mechanisms for discordant cell-free DNA testing results, including fetoplacental mosaicism, cotwin demise, and maternal genetic aberrations. Therefore, cell-free DNA testing is not diagnostic. Cell-free DNA testing can also incidentally detect conditions such as maternal malignancy. For these reasons, appropriate pre- and posttest counseling regarding the risks, benefits, limitations, and clinical utility of cell-free DNA testing is paramount.