Abstract：
OBJECTIVE: To evaluate non-invasive prenatal testing (NIPT) and expanded non-invasive prenatal testing (NIPT-plus) for detecting aneuploidies at different sequencing depths and assess Z-score accuracy in predicting trisomies 21, 18, 13, 45X, and 47XXX.
METHODS: Pregnancies with positive NIPT or NIPT-plus results detected at the prenatal diagnosis center of Nanfang Hospital were included in this retrospective study, between January 2017 and December 2022. Invasive prenatal diagnostic results were collected. Logistic regression analyses were used to study the relationship between Z-score and positive predictive value (PPV). Optimal cut-off values were obtained based on receiver operating characteristic analysis, and PPVs were calculated in different groups.
RESULTS: We evaluated 1348 pregnant women with positive results, including 930 reported by NIPT and 418 reported by NIPT-plus. NIPT reported significantly more rare chromosomal aneuploidies (RCAs), and NIPT-plus had a significantly higher PPV for trisomy 21 (T21). Logistic regression analyses showed a significant association (P < 0.001) between Z-score and PPVs for T21 and trisomy 18 (T18). A linear relationship was observed between fetal fraction (FF) and Z-values in the true positive cases of T21 and T18.The high Z-score group had significantly higher PPVs than the low Z-score group for T21, T18, trisomy 13, and 47XXX, but not for 45X.
CONCLUSIONS: The Z-score is helpful in assessing NIPT or NIPT-plus results. Therefore, we suggest including the Z-score and FF in the results. By combining the Z-score, FF, and maternal age, clinicians can interpret NIPT results more accurately and improve personal counsel to reduce patients\' anxiety.
METHODS: Pregnancies with positive NIPT or NIPT-plus results detected at the prenatal diagnosis center of Nanfang Hospital were included in this retrospective study, between January 2017 and December 2022. Invasive prenatal diagnostic results were collected. Logistic regression analyses were used to study the relationship between Z-score and positive predictive value (PPV). Optimal cut-off values were obtained based on receiver operating characteristic analysis, and PPVs were calculated in different groups.
RESULTS: We evaluated 1348 pregnant women with positive results, including 930 reported by NIPT and 418 reported by NIPT-plus. NIPT reported significantly more rare chromosomal aneuploidies (RCAs), and NIPT-plus had a significantly higher PPV for trisomy 21 (T21). Logistic regression analyses showed a significant association (P < 0.001) between Z-score and PPVs for T21 and trisomy 18 (T18). A linear relationship was observed between fetal fraction (FF) and Z-values in the true positive cases of T21 and T18.The high Z-score group had significantly higher PPVs than the low Z-score group for T21, T18, trisomy 13, and 47XXX, but not for 45X.
CONCLUSIONS: The Z-score is helpful in assessing NIPT or NIPT-plus results. Therefore, we suggest including the Z-score and FF in the results. By combining the Z-score, FF, and maternal age, clinicians can interpret NIPT results more accurately and improve personal counsel to reduce patients\' anxiety.
摘要：
目的：评估非侵入性产前检测（NIPT）和扩展非侵入性产前检测（NIPT-plus），以检测不同测序深度的非整倍体，并评估Z评分在预测三体21、18、13、45X中的准确性。47XXX。
方法：将在南方医院产前诊断中心检测到的NIPT或NIPT+结果阳性的孕妇纳入本回顾性研究。2017年1月至2022年12月。收集侵入性产前诊断结果。采用Logistic回归分析研究Z评分与阳性预测值(PPV)的关系。基于接收机工作特性分析，得到了最佳截止值，计算不同组的PPVs。
结果：我们评估了1348名阳性结果的孕妇，包括NIPT报告的930和NIPT+报告的418。NIPT报道了明显更罕见的染色体非整倍体（RCAs），对于21三体（T21），NIPT+有明显更高的PPV。Logistic回归分析显示，T21和18三体（T18）的Z评分与PPV之间存在显着关联（P<0.001）。在T21和T18的真阳性病例中，胎儿分数（FF）与Z值之间存在线性关系。对于T21，T18，13三体和47XXX，高Z评分组的PPV明显高于低Z评分组，但不是45X。
结论：Z评分有助于评估NIPT或NIPT+结果。因此,我们建议在结果中加入Z评分和FF.通过组合Z分数，FF,和产妇年龄，临床医生可以更准确地解释NIPT结果，并改善个人咨询，以减少患者的焦虑。
方法：将在南方医院产前诊断中心检测到的NIPT或NIPT+结果阳性的孕妇纳入本回顾性研究。2017年1月至2022年12月。收集侵入性产前诊断结果。采用Logistic回归分析研究Z评分与阳性预测值(PPV)的关系。基于接收机工作特性分析，得到了最佳截止值，计算不同组的PPVs。
结果：我们评估了1348名阳性结果的孕妇，包括NIPT报告的930和NIPT+报告的418。NIPT报道了明显更罕见的染色体非整倍体（RCAs），对于21三体（T21），NIPT+有明显更高的PPV。Logistic回归分析显示，T21和18三体（T18）的Z评分与PPV之间存在显着关联（P<0.001）。在T21和T18的真阳性病例中，胎儿分数（FF）与Z值之间存在线性关系。对于T21，T18，13三体和47XXX，高Z评分组的PPV明显高于低Z评分组，但不是45X。
结论：Z评分有助于评估NIPT或NIPT+结果。因此,我们建议在结果中加入Z评分和FF.通过组合Z分数，FF,和产妇年龄，临床医生可以更准确地解释NIPT结果，并改善个人咨询，以减少患者的焦虑。
