Normality of MoM of screening indexes for Down¬ðs syndrome

    SHEN Qiª²Jun, NIE Liangª²Hua, L¦a Wenª²Bo

    Institute of Preventive Medicine, School of Medicine, Ningbo University, Ningbo 315211, China, First Yangzhou Hospital, Medical College, Southeast University, Yangzhou 222500, China, Department of Biotechnology, College of Life Sciences, Zhejiang University, Hangzhou 310058, China

    ¡¾Abstract¡¿ AIM: To explore the normality of MoM values of AFP and HCG used to screen the Down¬ðs syndrome in Jiangsu province, and discuss the feasibility and effectiveness of application of SL transformation in Johnson system of distributions which is used to normalize MoM values of indexes above. METHODS: The data were obtained from the research project on birth defect intervention in Jiangsu province . SL transformation in lognormal distribution and Johnson distribution system was used to normalize MoM values of AFP and hCG in prenatal screening for Down¬ðs syndrome. RESULTS: The MoM values of AFP and HCG were both not of normal distribution. Through the lognormal distribution of MoM values, AFP was in accord with normal distribution and hCG was not. Normality of HCG MoM became better at Z=0.31. CONCLUSION: It is suitable for the indexes of prenatal screening for Down¬ðs syndrome in our country to use SL normality transformation in Johnson system of distributions. ......