A high risk of Down’s screening means that the fetus is at high risk for chromosomal aneuploidy disorders. Down’s screening in early pregnancy is 85% accurate, but there is a 5% false positive rate. Combined midtrimester Down’s syndrome screening has an accuracy rate of 60-75% with a 5% false positive rate. Non-invasive genetic testing is performed by drawing the pregnant woman’s blood for fetal free DNA to detect the possibility of trisomy 21, trisomy 18, and trisomy 13, with an accuracy rate of over 99% and a false-positive rate of <1%. However, neither Down's syndrome screening nor non-invasive genetic testing can confirm whether the fetus has chromosomal abnormalities, and prenatal diagnosis must be performed to check whether the fetus has chromosomal abnormalities to confirm the diagnosis.