How is the test done?
Your doctor will take a sample of amniotic fluid or chorionic villi and send it to our laboratory. A scientist will prepare the sample and perform the test overnight. At present we check for five of the chromosomes (X, Y, 13, 18 and 21). These chromosomes are the ones most often found associated with abnormality.

How long does the FastDNA test take?
It will take 1-2 working days to get a result.

If my result is not abnormal, does that mean my baby has normal chromosomes?
Not necessarily. About 90% of the chromosome errors seen by cytogeneticists involve extra copies or loss of chromosomes X, Y, 13, 18 or 21. If we do not find a problem with your FastDNA test for these chromosomes it is unlikely (but not impossible) that your baby has a chromosome abnormality. The other chromosomes will be revealed, however, by the standard karyotype that always follows.

Is the result always correct?
In most cases the results are correct. However, for most scientific and medical tests there is a small risk of an abnormal result when there is not really an abnormality (false positive). There is also a small risk of getting a normal result when there is really an abnormality (false negative). From published studies we know that the chance of a false result is less than ≤6 in 10,000.

What if the test is abnormal?
Your doctor will contact you and discuss with you what the scientists have found. They will be able to tell you what the abnormality means for your baby.

Do I still need to have routine chromosome analysis as well as FastDNA?
Yes. We must still check all of the other chromosomes and check that the chromosomes X, Y, 13, 18 and 21 look completely intact.

What if the test fails?
We will contact your doctor if this happens. We will still get a result from the routine chromosome analysis. If we do not get a meaningful result from FastDNA you will not be charged for the DNA test. About <1/3000 fails to give a result.

What is the advantage of the FastDNA test?
Most people find it difficult waiting a week or more for the result of the chromosome test. We know that it is even harder when your doctor has found a problem with your baby on ultrasound. The FastDNA test allows us to find most of the chromosome abnormalities quickly.