RESUMEN
Objective To explore the regional parameters of triple screening model of Down syndrome in the second trimester in Jinhua City.Methods A total of 20 232 second trimester pregnant women with single fetus (gestational age at 15 -20 +6 weeks)was enrolled,and their serum samples were determined by American Perkin Elmer company Auto DELFIA automatic time -resolved fluorescence immunoassay analyzer for Down syndrome screening with triple markers, namely AFP,free β-hCG and uE3 .The risks of Down syndrome were evaluated by Lifecycle 3.2 software.And the risks of Down syndrome were re -calculated by local statistical median equations.Pregnant women were suggested to receive amniotic fluid fetal karyotype analysis if the risk of Down syndrome were equal or above 1 /270.Results Local median marker levels were significantly higher than the software built -in median levels (P <0.01).Both true -positive detection rates (sensitivity)were 87.50%.The false positive rate of local median equations was 4.24%,while the built -in median equations was 4.74%.Conclusion There are significant differences on the race and region by using the LifeCycle 3.2 median equations.The local equations may lower the false positive rate.