天津医药

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建立天津地区孕中期唐氏综合征筛查人群中位数系统的研究

姚静怡1,张颖2,辛力1,崔岚1,岳胜1,谢晓媛3   

  1. 1. 天津医科大学；天津市妇女儿童保健中心
    2. 天津医科大学总医院
    3. 天津市妇女儿童保健中心筛查中心
  • 收稿日期:2011-07-15 修回日期:2011-11-03 出版日期:2012-05-15 发布日期:2012-05-15
  • 通讯作者: 姚静怡

Medians for second-trimester Down syndrome screening in Tianjin

  • Received:2011-07-15 Revised:2011-11-03 Published:2012-05-15 Online:2012-05-15
  • Contact: Jing-yi YAO

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摘要： 目的 建立天津地区孕中期唐氏综合征筛查人群中位数系统，探讨其临床应用的价值。方法 采用时间分辨荧光分析法检测100 543例妊娠14～20＋6周妊娠妇女血清甲胎蛋白（AFP）和游离绒毛促性腺激素（Free β-hCG）的浓度。利用唐氏综合征筛查风险评估软件（LC3.0）的Medians Tool统计其中61 881例不同孕周AFP和Free β-hCG的人群中位数、体质量，对LC3.0的中位数方程、体质量校正方程系数进行修正。对另外38 662例妊娠妇女AFP和Free β-hCG的中位数漂移情况进行监控及调整，建立天津地区孕中期唐氏综合征筛查人群中位数系统。另选取13 001例妊娠15～20＋6周妊娠妇女测定其AFP和 Free β-hCG激素水平，分别利用高加索人群中位数系统和已建立的人群中位数系统进行孕中期唐氏综合征筛查，设定1/270为唐氏综合征高风险切割值。≥1/270为唐氏综合征筛查高风险。并通过Medians Tool将13 001例妊娠妇女AFP和Free β-hCG的中位数，体质量与已建立的中位数曲线、体质量曲线进行拟合，检测其吻合度。结果 经染色体核型分析，13 001例妊娠妇女中共确诊唐氏综合征9例。以高加索人群中位数系统进行筛查的检出率为77.78%，假阳性率为8.30%，，阳性预测值为6.49‰。利用已建立的人群中位数系统进行筛查的检出率为77.78%，假阳性率为5.33%，阳性预测值为10.00‰。其中13001例妊娠妇女的中位数与已建立的中位数方程是吻合的，AFP和 Free β-hCG的Median Factor分别为1.01、1.00。结论 天津地区孕中期人群AFP和Free β-hCG与高加索人群存在差异，利用已建立的中位数系统进行孕中期唐氏综合征筛查，可以有效降低假阳性率，提高筛查效率。

关键词: 中位数, 孕中期血清学筛查, 唐氏综合征

Abstract: Abstract Objective: To establish the medians of maternal serum alpha-fetoprotein (AFP) and free human chorionic gonadotropin (Free β-hCG) for second trimester Down syndrome screening in Tianjin district, in order to discuss its clinical medical value. Method: We measured serum level of AFP and Free β-hCG from 100,543 pregnancies ranged from 14 weeks to 20+6 weeks using time-resolved fluoroimmunoassay. The Medians Tool of the PE risk assessment software（LC3.0） was used to determine 61,881 pregnancies’ serum AFP and free β-hCG medians value, modified by median coefficients，and established the Weight equation. 38,662 pregnancies’ serum AFP and free β-hCG levels were adjusted by median shift to establish median values system for second-trimester Down syndrome screening .Other 13,001 pregnancies’ serum AFP and free β-hCG levels were measured. The screening results were calculated using the standard algorithm based on the Caucasian median value system and the Tianjin median value system. Patients with an increased risk of Down syndrome pregnancy (≥270) were offered genetic amniocentesis. Result: Medians from 13,001 pregnancies matched the established median formula. The Median factor of AFP and free β-hCG were 1.01 and 1.00respectively. The detection rate （DR）of the Tianjin median value system for second-trimester Down syndrome screening was 77.78%, false positive rate（FDR） was 5.33%, positive predictive value was 10.00‰,and the DR based on the Caucasian median value system was 77.78%, the FDR was 8.30%, positive predictive value was 6.49‰. Conclusion: Ethnic variance exists between the Caucasian and Tianjin populations. The accuracy of screening is increased by the use of race-specific medians.

Key words: Median value, second-trimester serum screening, Down syndrome