Cell-Free Fetal DNA Test in Mt. Blood

(cff DNA – Cell-Free Fetal DNA)

(Nipt - Non-Invasive Prenatal Test)

It is a very important invention in terms of pregnancy follow-up and screening tests.
It was put into clinical use in 2011. In the following years, the number of laboratories performing the test and detection rates has been increased.
Some of the free DNA circulating in maternal blood is from fetus and the placenta. With the help of these DNAs, it is possible to screen Down Syndrome with high sensitivity (99% -99.5%).
The most frequently screened chromosomes; 21, 18, 13 and sex chromosomes.
As the genetic technology and knowledge accumulate, the number of fetal disorders and possibly maternal diseases t detected might increase. The most important field of application accepted as of 2019 is Down Syndrome (Trizomy 21).
It is preferred to have it after the 10th gestational week. If fetal DNA cannot be ectracted at the desired amount in maternal serum, the test can be repeated.
Depending on the country and test done, the result is ready within 7-14 days
It can also be performed in Twin pregnancy.
Not a definitive test. If positive the result must be verified with a diagnostic test. (Amniocentesis / Cordocentesis / CVS)
With decreasing cost every year, uptake of this test has been increased. But Probabaly it will take some more time to use cff-DNa test routinely for all pregnant women.
Although there are discussions about whom test should be done, following groups of pregnant women would be the candidates;

- Advanced Maternal Age

- Mild ultrasonography findings for chromosomal abnormalities

- Increased risk in Combined or Quad Screening test

- Family request or preference

- A history of pregnancy with Down Syndrome and normal ultrasonography findings in the current pregnancy

It should not be performed in the presence of prominent anomalies and strong ultrasonography findings. Instead, a diagnostic test should be performed.
This test is not a substitute for 11-14 weeks Ultrasound Scan