Prenatal Cell-Free DNA Screening Test
Prenatal cell-free DNA (cfDNA) screening is a blood test that checks the baby's DNA in the mother's blood to see if the baby is more likely to have certain chromosome disorders, such as Down syndrome.
What this test measures
This test measures cell-free DNA from the fetus in the mother's blood to screen for an increased risk of trisomy disorders (extra chromosomes), such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). It can also determine the baby's sex and check Rh blood type.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
A positive result means there is an increased risk that your baby has Down syndrome or another trisomy disorder, but it does not confirm the diagnosis. Follow-up diagnostic tests are needed.
Lower-than-normal results
A negative result means it's unlikely that your baby has Down syndrome or another trisomy disorder.
Frequently asked questions
What is prenatal cell-free DNA screening?
It is a blood test given during pregnancy that checks the baby's DNA in the mother's blood to see if the baby is more likely to have certain chromosome disorders.
What conditions does the test screen for?
It screens for Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13). It can also determine the baby's sex and check Rh blood type.
When can the test be done?
The test can be done as early as the 10th week of pregnancy.
What does a positive result mean?
A positive result means there is an increased risk that your baby has a chromosome disorder, but it does not confirm the diagnosis. You will need other tests like amniocentesis or CVS to confirm.
Is the test safe?
Yes, there is very little risk to you and your baby from the blood test itself.
Related lab tests
Sources
- MedlinePlus: Prenatal Cell-Free DNA Screening — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.