Why is a cell-free DNA test done?
The test is used to look for genetic conditions caused by too many or too few chromosomes, such as trisomy 18 and Down syndrome (trisomy 21).
How is a cell-free DNA test done?
A health professional uses a needle to take a blood sample, usually from the arm.
How do you prepare for a cell-free DNA test?
In general, there's nothing you have to do before this test, unless your doctor or midwife tells you to.
What do the results of a cell-free fetal DNA test mean?
The fetal DNA will be looked at to see if there are missing or extra chromosomes. If there is an extra or missing chromosome (a positive result), your baby may have a genetic condition. A negative result means that your baby is unlikely to have one of the genetic conditions this test looks for.
This test can find up to 99% of trisomies such as 18 and 21. That means that it will find these conditions up to 99 times out of 100 and won't find them 1 time out of 100.
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