# Implementation of circulating cell-free DNA screening for fetal aneuploidies

## TL;DR

This paper discusses the use of cell-free DNA screening during pregnancy to detect fetal chromosomal abnormalities with high accuracy.

## Contribution

The paper highlights the implementation and effectiveness of cfDNA screening in prenatal programs.

## Key findings

- cfDNA screening has detection rates exceeding 99% for trisomy 21.
- The test has very low false-positive and false-negative results.
- cfDNA screening is non-invasive and has been integrated into prenatal screening programs in some countries.

## Abstract

Circulating cell-free DNA (cfDNA) consists of extracellular DNA fragments that circulate in the bloodstream and derived from apoptotic cells such as hematopoietic cells or placental trophoblast cells during pregnancy.

cfDNA screening has been included in prenatal screening programs for the detection of chromosomal abnormalities. Unlike other invasive techniques, such as amniocentesis or chorionic villus sampling, cfDNA screening only requires a maternal plasma test. The use of advanced technologies for cfDNA testing, including DNA sequencing and SNP arrays, enables the detection of pregnancies at risk for trisomy 21, 18 or 13.

This test has demonstrated a high accuracy and reliability, with detection rates exceeding 99 % for trisomy 21, and a very low rate of false-positive and false-negative results. In some countries, cfDNA screening has already been integrated in combined or universal prenatal screening programs.

As new technologies emerge and become widely available, more accurate prenatal tests will be developed for other genetic abnormalities.