Patient's question:
I am four months pregnant, and the doctor said I need a Down syndrome screening. I would like to ask what the difference is between Down syndrome screening and non-invasive DNA testing?Doctor's answer:
Down syndrome screening uses serum super value to estimate the risk of the fetus suffering from trisomy 21, trisomy 18, and neural tube defects. Non-invasive prenatal testing (NIPT) is mainly targeted at pregnant women with "high risk" results from Down syndrome screening. Down syndrome screening is cost-effective, safe, convenient, a mandatory prenatal test, non-invasive, but has a high rate of false positives despite its high detection rate and accuracy. NIPT has a high detection rate and accuracy, but a narrower testing scope, and cannot test for twin pregnancies or mosaicism chromosomal abnormalities. However, the scope of NIPT testing has already covered common chromosomal aneuploidy diseases. If the results from Down syndrome screening are normal, there is no need to undergo NIPT.