What is the difference between non-invasive DNA and amniocentesis?

Both non-invasive DNA and amniocentesis may be tests that need to be done during pregnancy, mainly to determine and understand whether the fetus has some congenital defects or diseases, but non-invasive DNA and amniocentesis cannot replace each other.

1. First, the advantages and disadvantages of various inspections

Down syndrome screening advantages and disadvantages:

① Advantages: economical (two to three hundred yuan), non-invasive (only venous blood needs to be drawn)

② Disadvantages: low detection rate and accuracy (even the most comprehensive combined early and mid-stage screening can only detect 80-90% of children with Down syndrome), high false positive rate (a large proportion of those who are screened for high risk of Down syndrome are not diagnosed after confirmation).

2. Advantages and disadvantages of non-invasive DNA:

① Advantages: non-invasive (only venous blood needs to be drawn), high detection accuracy (99% of children can be detected), and low false positive rate (non-invasive high-risk patients are rarely diagnosed as such).

② Disadvantages: high cost (ranging from more than 2,000 to 3,000 across the country), narrow detection scope (currently targeting trisomy 21, 18, and 13), high accuracy, slightly lower accuracy for sex chromosomes, and limited accuracy for other chromosomes (other chromosomal abnormalities often also manifest as high risk for Down syndrome screening). However, the scope of non-invasive testing already covers common chromosomal aneuploidy diseases.

3. Advantages and disadvantages of amniocentesis:

①Advantages: It can detect 46 chromosomes at a time, not only abnormalities in number, but also structural abnormalities >10M. In addition, gene chip and single gene disease testing can be performed. It has high accuracy (the gold standard for diagnosing chromosomal diseases) and is one of the prenatal diagnostic technologies with the widest detection range and highest accuracy.

② Disadvantages: There are certain risks (miscarriage rate 0.5-1‰), and in rare cases, cell culture may fail, requiring other examinations or re-puncture.