Prenatal chromosome abnormality testing
Fetal chromosome abnormality test
Common chromosome abnormalites found during pregnancy include numerical gain or loss of chromosomes, which is also referred to as chromosome aneuploidy. An example of chromosome gain in pregancy is trisomy (3 copies) of chromosome 21, otherwise known as Trisomy 21 or Down syndrome. There are other chromosome aneuploidy abnormalities that can be found during pregnancy.
Testing for chromosome abnormalities during pregnancy can be performed on chorionic villus (placenta) or amniotic fluid samples, however results are typically not available until 10-14 days. The chromosome test takes this long because the cells must be cultured or grown for ~7-10 days before being anlaysed.
We understand this can be a stressful time while waiting for the test results on your baby, particularly if your doctor has found an abnormality on ultrasound. Fortunately, our Fetal Aneuploidy Screening Test (Fast) DNA tests can provide a rapid test result within 2 working days.
For more information on fetal chromosome testing, see Cytogenetics - chromosome testing.
FastDNA or FastDNAplus
The FastDNA tests are used for rapid chromosome screening of the 5 most commonly found abnormalities involving chromosomes X, Y, 13, 18 and 21. DNA is extracted from the sample and the PCR technique (see PCR) is used to identify specific genetic markers on these chromosomes which can determine the number of chromosomes; e.g 2 or 3 copies of chromosome 21. Two copies of a chromosome indicates a normal result and 3 copies (trisomy) indicates an abnormal result.
FastDNAplus differs from FastDNA in that this test can also detect the deltaF508 mutation that is one of the causes of Cystic fibrosis.
This rapid test is only offered as an add-on test to the standard fetal chromosome test (above).
For more information on FastDNA testing, see FastDNA testing.