Genetics Northern California


Cell-free DNA screening is an optional blood test done during pregnancy. This test looks for certain chromosome conditions in a developing baby. It is also called non-invasive prenatal testing (NIPT).  

When can cfDNA screening be done?
cfDNA can be done after 10 weeks of pregnancy (ideally between 11 to 21 weeks). 

What does cfDNA screen for? 
This test screens for conditions caused by too many or too few chromosomes, including Down syndrome, trisomy 18, and trisomy 13.

When requested, cfDNA can also screen for sex chromosome conditions, including Turner syndrome, Klinefelter syndrome, XXX syndrome, and XYY syndrome.

It does not screen for any other chromosome conditions or other birth defects. 

Can cfDNA predict fetal sex? 
Yes, cfDNA can predict fetal sex. If you want to know, this can be included in the test results.  

How does cfDNA work? 
The test looks at bits of fetal DNA that can be found in the blood during pregnancy. These small bits of fetal DNA come mainly from the placenta. 

What type of results could I get? 
  • Screen negative: This result means the baby is unlikely to have any of the conditions the test looks for. 
  • Screen positive: This means the baby might have a chromosome condition. More testing is offered to find out for sure. 

Sometimes cfDNA screening does not give a result. When this happens, the test may be done a second time. 

NIPT video

Last reviewed: September 21, 2022
Reviewed by:   Kimberly Barr, LCGC       
                      Kaiser Permanente NCAL Regional Genetics