Cell Free DNA Testing is a new technology that is a screening test for chromosomal abnormalities such as Down’s Syndrome and Edward’s Syndrome.
This is a test that looks at fetal DNA that is found in the mother’s blood stream. It requires a blood draw from the mother and can be performed as early as 10 weeks.
The fetal DNA is then evaluated to look for chromosomal abnormalities such as Down’s and Edward’s syndrome.
The benefits in comparison to other screening tests is that it has a lower false positive rate (0.5% in comparison to 4.2%, for Down’s and Edward’s syndrome combined). The benefit of a lower false positive is that fewer women will have a need to undergo invasive procedures such as amniocentesis and chorionic villi sampling (CVS). Typically if a woman has an abnormal fetal screening test, they are then offered and or encouraged to undergo an amniocentesis or CVS. With these procedures fetal cells are taken from the amniotic fluid or placenta.
The drawback of these procedures is the risk. Complications of amniocentesis and CVS include infection, preterm delivery and fetal death.
Another drawback of this new technology is the cost. It may cost as much as $2,000 depending on insurance coverage. Currently, insurance carriers only cover this new testing for a specific indication. The indications include: women that will be 35 years of age or greater at the time of delivery, women who have an abnormal anatomical finding at the time of their ultrasound, or women that have had a previous pregnancy with a chromosomal abnormality. Remember, every insurance carrier is different and their definition of “covering a test” varies.
Despite the few drawbacks of this test, this is extremely exciting technology! Many physicians, including myself, believe that one day invasive testing with risks to pregnancy will be completely replaced by these advances in science.