Further tests such as amniocentesis or non-invasive prenatal genetic testing are recommended for high risk of trisomy 21, which have a higher accuracy rate than general Down screening. The accuracy rate of the screening test itself is only about 60%, which means that whether the result of the screening test is high or low risk, it only indicates a high or low probability of Down’s syndrome, and it does not mean that if the result of the screening test is high risk, you will definitely have Down’s syndrome, because in clinical practice, many pregnant women with high risk of Down’s syndrome later undergo further tests, such as amniocentesis or non-invasive prenatal genetic testing, but the result indicates The accuracy rate of amniocentesis or non-invasive prenatal genetic testing can be as high as 99%. So if you find a high risk of trisomy 21 during the maternity test, you need to do a non-invasive prenatal genetic test, because amniocentesis has the risk of inducing miscarriage, so some pregnant women are reluctant to do it. In short, when the risk of trisomy 21 is high, do not panic too much, and then do a non-invasive prenatal genetic test to further confirm the diagnosis, some results suggest that it is normal, then it means that there is no problem, if the results also suggest high risk, then it suggests that the probability of Down syndrome is very high, then the physician may recommend termination of pregnancy.