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

The main difference between amniocentesis and non-invasive prenatal DNA testing lies in the fact that the former is a prenatal diagnostic method, while the latter is a prenatal screening method. Non-invasive prenatal DNA testing primarily involves analyzing the mother's blood to determine whether fetal chromosomes are abnormal. However, this method can only detect abnormalities in chromosome number, and cannot identify chromosomal translocations or inversions. In contrast, amniocentesis can definitively determine whether the fetus has chromosomal abnormalities by directly obtaining the fetal karyotype, offering higher accuracy and comprehensiveness. Therefore, if a pregnant woman's Down syndrome screening or non-invasive DNA test results indicate high risk, further amniocentesis is required.