摘要目的:探讨孕妇外周血胎儿游离DNA(cell-free fetal DNA，cffDNA)检测全流程中导致检测失败的因素以及实验室内重复检测的策略及结果。方法:收集2021年2月至2022年12月在西北妇女儿童医院医学遗传中心就诊并接受外周血cffDNA检测的孕妇36 301例，根据实验室内质控要求和流程进行重复检测。对孕妇外周血cffDNA检测失败的因素和重复检测的结果进行分析。结果:36 301例接受外周血cffDNA检测孕妇中，首次检测未取得有效结果需要重复检测孕妇999例，重复检测率为2.75%(999/36 301)。孕妇外周血cffDNA检测整个流程中，样本需要重复检测的主要原因是测序后存在单条染色体数据波动，重复检测后有92.99%(929/999)的样本得到有效结果，其中85.69%(856/999)为低风险，7.31%(73/999)为高风险，7.01%(70/999)再次检测失败，孕妇外周血cffDNA检测失败率为0.19%(70/36 301)。最终检测失败的主要原因也是单条染色体数据波动。结论:在严格的实验质量管理与控制下，孕妇外周血cffDNA检测失败是客观存在且不可避免的，检测前要做好遗传咨询告知。测序后存在单条染色体数据波动是检测失败的主要原因，重复检测成功率较高，可有效提高最终检测成功率。

abstractsObjective:To explore the factors leading to test failure in the whole process of cell-free fetal DNA (cffDNA) in pregnant women and the strategy and result of repeated testing in the laboratory.Methods:CffDNA testing was performed on 36 301 pregnant women who came to Center of Medical Genetics of Northwest Women’s and Children’s Hospital from February 2021 to December 2022. Repeat testing was performed according to the laboratory quality control requirements and procedures. Factors contributing to failure to perform maternal peripheral blood cffDNA testing and results of repeat testing were analyzed.Results:Among the 36 301 samples who received maternal peripheral blood cffDNA test, 999 samples required repeat test without the first effective results, and the repeat test rate was 2.75% (999/36 301). In the whole process of maternal peripheral blood cffDNA testing, the main reason is that samples had single chromosome data fluctuations after sequencing, 92.99% (929/999) of samples obtained effective results after repeated testing, of which 85.69% (856/999) were low risk, 7.31% (73/999) were high risk, 7.01% (70/999) failed again. Pregnant peripheral blood cffDNA failure rate was 0.19% (70/36 301). The main reason for the failure of the final detection is also the fluctuation of the single chromosome data.Conclusion:Under the strict experimental quality management and control, the failure of peripheral blood cffDNA test of pregnant women is objective and inevitable, and genetic counseling should be done before testing. The fluctuation of single chromosome data after sequencing is the main reason for detection failure. The high success rate of repeated detection can effectively increase the final success rate of repeated detection.