Abstract：
UNASSIGNED: Non-invasive prenatal testing (NIPT) has been widely adopted as an approach for foetal aneuploidy screening. This study was to evaluate the performance of NIPT for foetal T21 detection in subgroups of pregnancies and the correlation between Z-score and discordant positive predictive values (PPVs).
UNASSIGNED: We retrospectively reviewed the NIPT results among 22361 pregnancies undergoing combined second-trimester screening (cSTS) previously. Sixty-four cases with positive NIPT results for foetal T21 were validated by invasive prenatal diagnosis.
UNASSIGNED: In pregnancies with cSTS-T21 low-, intermediate-, and high-risk, the PPVs at NIPT were 14.3%, 64.3%, and 86.4%, respectively. Mean Z-scores of positive NIPT cases with cSTS-T21 high- and intermediate-risk were comparable, while were higher than that of cases with pre-test low-risk. Furthermore, PPVs for positive NIPT cases at 3 < Z < 5, 5 ≤ Z < 9, and Z ≥ 9 were 16.7%, 63.2%, and 100.0%, respectively.
UNASSIGNED: This study suggested that Z-score value of positive cases might be associated with discordant PPVs for T21 screening in subgroups of pregnancies.
Non-invasive prenatal testing has been offered as a primary screening option to high-risk or general pregnancy. However, the accuracy of non-invasive prenatal testing in patients with various pre-test risks remained unveiled. The current study revealed that the true positive probability for foetal trisomy 21 screening in pregnancies with prior high-risk was higher than that in pregnancies of intermediate-risk, and both of them were much higher than that of those with pre-test low-risk. The average of Z-score for chromosome 21 of positive non-invasive prenatal testing case in high-risk group was comparable with that of intermediate-risk group, while was higher than that of low-risk group. There was also an upward trend for the true positive probability of foetal trisomy 21 screening with the increase of Z-score. Our study revealed that pre-test risk and Z-score for chromosome 21 were helpful for accurately interpreting the reliability of positive results for foetal trisomy 21.
UNASSIGNED: We retrospectively reviewed the NIPT results among 22361 pregnancies undergoing combined second-trimester screening (cSTS) previously. Sixty-four cases with positive NIPT results for foetal T21 were validated by invasive prenatal diagnosis.
UNASSIGNED: In pregnancies with cSTS-T21 low-, intermediate-, and high-risk, the PPVs at NIPT were 14.3%, 64.3%, and 86.4%, respectively. Mean Z-scores of positive NIPT cases with cSTS-T21 high- and intermediate-risk were comparable, while were higher than that of cases with pre-test low-risk. Furthermore, PPVs for positive NIPT cases at 3 < Z < 5, 5 ≤ Z < 9, and Z ≥ 9 were 16.7%, 63.2%, and 100.0%, respectively.
UNASSIGNED: This study suggested that Z-score value of positive cases might be associated with discordant PPVs for T21 screening in subgroups of pregnancies.
Non-invasive prenatal testing has been offered as a primary screening option to high-risk or general pregnancy. However, the accuracy of non-invasive prenatal testing in patients with various pre-test risks remained unveiled. The current study revealed that the true positive probability for foetal trisomy 21 screening in pregnancies with prior high-risk was higher than that in pregnancies of intermediate-risk, and both of them were much higher than that of those with pre-test low-risk. The average of Z-score for chromosome 21 of positive non-invasive prenatal testing case in high-risk group was comparable with that of intermediate-risk group, while was higher than that of low-risk group. There was also an upward trend for the true positive probability of foetal trisomy 21 screening with the increase of Z-score. Our study revealed that pre-test risk and Z-score for chromosome 21 were helpful for accurately interpreting the reliability of positive results for foetal trisomy 21.
摘要：
非侵入性产前检测（NIPT）已被广泛采用作为胎儿非整倍体筛查的方法。这项研究旨在评估NIPT在妊娠亚组中检测胎儿T21的性能以及Z评分与不一致阳性预测值（PPV）之间的相关性。
■我们回顾了22361例妊娠合并中期筛查（cSTS）的NIPT结果。通过侵入性产前诊断验证了64例胎儿T21的NIPT结果阳性。
■在低cSTS-T21妊娠中，中介-，高风险，NIPT的PPV为14.3%，64.3%,和86.4%，分别。CSTS-T21高危和中危NIPT阳性病例的平均Z评分相当，而高于测试前低风险的病例。此外，3■这项研究表明，阳性病例的Z评分值可能与妊娠亚组T21筛查的不一致PPV相关。
非侵入性产前检测已被提供作为高危妊娠或一般妊娠的主要筛查选择。然而,在有各种测试前风险的患者中,非侵入性产前检测的准确性仍然存在.目前的研究表明，在先前高风险的怀孕中，胎儿21三体筛查的真正阳性概率高于中等风险的怀孕。两者都比预试低风险者高得多。高危组无创性产前检查阳性病例的21号染色体Z评分平均值与中危组相当，而高于低危组。随着Z得分的增加，胎儿21三体筛查的真实阳性概率也呈上升趋势。我们的研究表明，21号染色体的测试前风险和Z评分有助于准确解释胎儿21三体阳性结果的可靠性。
■我们回顾了22361例妊娠合并中期筛查（cSTS）的NIPT结果。通过侵入性产前诊断验证了64例胎儿T21的NIPT结果阳性。
■在低cSTS-T21妊娠中，中介-，高风险，NIPT的PPV为14.3%，64.3%,和86.4%，分别。CSTS-T21高危和中危NIPT阳性病例的平均Z评分相当，而高于测试前低风险的病例。此外，3
非侵入性产前检测已被提供作为高危妊娠或一般妊娠的主要筛查选择。然而,在有各种测试前风险的患者中,非侵入性产前检测的准确性仍然存在.目前的研究表明，在先前高风险的怀孕中，胎儿21三体筛查的真正阳性概率高于中等风险的怀孕。两者都比预试低风险者高得多。高危组无创性产前检查阳性病例的21号染色体Z评分平均值与中危组相当，而高于低危组。随着Z得分的增加，胎儿21三体筛查的真实阳性概率也呈上升趋势。我们的研究表明，21号染色体的测试前风险和Z评分有助于准确解释胎儿21三体阳性结果的可靠性。
