Down's syndrome screening

特許 権利維持 Guidelines recommend screening for Down syndrome to be offered to all pregnant women, regardless of age.[61][62] A number of tests can be used, with varying levels of accuracy. They are usually used in combination to increase the detection rate, while maintaining a low false-positive rate.[12] None can be definitive, thus if screening is positive, either amniocentesis or chorionic villous sampling is required to confirm the diagnosis.[61] Screening in both the first and second trimesters is better than just screening in the first trimester.