Application Lifecycle 2T And Two Prenatal Screening For Down Syndrome Risk Calculation Software In China Pregnant Population

Objective The individual risk assessment of fetal Down’s syndrome based on maternal age, optionally complemented by the determination of AFP, free beta HCG and uE3has progressively supplanted other search strategies for fetal aneuploidies. It could be shown that this diagnostic strategy equally detects other numeric aneuploidies at a comparable rate. A positive test result is also predictive for the presence of a fetal malformation, In this field, several computer programs are available for clinical use. The objective of our study was to re-evaluate the first consecutive4580Down’s syndrome-risk calculations determined by2T program and to compare the risk calculation to Lifecycle program, software introduced in2007.Material and methods At the Department of Obstetrics and Gynecology, Peking union medical college,4580consecutive complete data sets comprising second trimester screening performed between Dec1,2007and Jan10,2009and corresponding fetal outcome were analysed using risk assessment based on the2T program and compared with the risk evaluation as determined by the Lifecycle program. A risk exceeding1:270was considered to indicate the need for further invasive testing. Comparison of risk evaluation for Down’s syndrome between2T and Lifecycle is performed on the calculation of detection rate and false positive rate.Results Among the4580cases,4574(99.81%) fetuses revealed to be cytogenetically healthy. Both softwares showed identical detection rates at the genetic and somatic level:6cases of Down-Syndrome (0.13%),3NTD(0.066%) were detected. At the level of genetic detection, the false positive rate rised from6.65%(2T)to8.35%(Lifecycle)(2.2%),which had droped from9.36%after adjustment.Conclusion The test performance of Lifecycle,with the identical detection rate of fetal aneuploidy as2T program and the false-positive rate higher,was inferior to that of2T,. Had Lifecycle been employed prospectively in our study,25%more women examined would have been offered unnecessarily an invasive procedure for fetal karyotyping. This results from the more sensitivity of Lifecycle for individual biochemical marker, because all the78false-positive cases in Lifecycle,not in2T,had a HCGMabve3.6.