There is no scientific basis for nine out of ten Downscreens being high.
Down’s syndrome screening is mainly to detect whether the fetus has an abnormal disease, although the accuracy rate is not as high as amniocentesis or non-invasive DNA testing, but the error is very small.
A high Down’s test may be a problem with the fetus, and the blood test indicators are usually abnormal, and the calculated risk value is high risk. There are measurement errors or fluctuations in hormone secretion in the body. Since the Down screening test mainly calculates the risk value based on the blood test results, if there is high secretion of human chorionic gonadotropin or alpha-fetoprotein, the test result may be high risk.
The claim that nine out of ten Down screening tests are high does not hold true because the high risk of Down screening is related to the age of the pregnant woman. Generally the older the pregnant woman is, the higher the probability of a Down screening test. It is recommended that if a pregnant woman has a high risk screening result, she needs to go to the hospital for amniocentesis or non-invasive DNA testing. For high-risk pregnant women who need prenatal diagnosis, further prenatal counseling and prenatal diagnosis should be conducted in a timely manner.