What does cell-free DNA screening primarily assess?

Cell-free DNA screening primarily assesses the presence of placental DNA in the maternal bloodstream, which is used to evaluate the risk of fetal aneuploidies, such as trisomy 21 (Down syndrome), trisomy 18, and trisomy 13. This non-invasive prenatal testing (NIPT) analyzes fragments of DNA that are released from the placenta into the mother's circulation. By examining the chromosomal makeup of this cell-free DNA, clinicians can identify abnormalities indicative of genetic conditions, allowing for early assessment and better pregnancy management.

The focus on placental DNA is crucial because it reflects the genetic material of the fetus, providing insights into potential aneuploidies without the need for invasive procedures, which carry associated risks. This method has become popular due to its high sensitivity and specificity compared to traditional screening methods.