Feasibility of screening AFP and free-β-HCG using serum samples gravidas at mid-gestation period

Objective To investigate the effect of screening data for Down's syndrome and neural tube defects by measuring serum AFP and free-β-HCG at mid-gestation period(14~20 weeks) that was being used in Chinese people.Methods Measured the maternal serum AFP and free-β-HCG using dual kit with Tr-FIA in 11 292 pregnant women at 14~20~(+6) weeks of gestation at Huzhou maternity and infant hospital and analyzed their risk results by the wallac company's software.Then compared them with the clinical results.Results There were 5 detected Down's syndrome(including 1 Robertsonian translocation case) and 2 undetected cases in 11 292 serum samples.Meanwhile,1 case of neural tube defects had been detected.The test sensitivity was 71.43%,the specificity was 96.47%,the diagnosis index was 67.9% and the screening positive rate was 3.57% for Down's syndrome.The screening positive rate was 0.30% for 18-trisomy sydrome,and 2 cases of 18-trisomy sydromes were detected.The test sensitivity was 100%,the specificity was 99.70%,and the diagnosis index was 99.70%.The test sensitivity was 100%,the specificity was 99.3%,the diagnosis index was 99.3% and the screening positive rate was 0.71% for neural tube defects.Conclusion The screening data of maternal serum for Down's syndrome and neural tube defects is applicable to Chinese people.However,for improving the effect of screening farther,to establish Chinese people's own median and cut-off point should be necessary.