Lüthgens K, Hoopmann M, Alkier R, Abele H, Yazdi B, Kagan K
Laboratory Medicine, Labor Prof. Enders und Partner, Stuttgart.
Department of obstetrics and gynaecology, University of Tübingen.
Ultraschall Med. 2012 Dec;33(7):E57-E61. doi: 10.1055/s-0031-1299083. Epub 2012 Jan 24.
Assessment of first-trimester combined screening for trisomy 18 and 13 with the combined use of the risk algorithms for trisomy 21, 18 and 13.
First-trimester combined screening based on maternal and gestational age, fetal NT, PAPP-A and free β-hCG was assessed in 39 ,004 pregnancies. Patient-specific risks for trisomy 21, 18, 13 were computed based on the current FMF London algorithm.
The study population consisted of 38 ,751 singleton pregnancies including 39 cases with trisomy 18 or 13. In the aneuploid group, median delta NT was 0.72 mm, PAPP-A was 0.21 MoM and free β-hCG was 0.33 MoM. Although only 41 % of the NT measurements of fetuses with trisomy 18 or 13 were above the 95th percentile, the detection rates for trisomy 18 or 13 were 82 % with the trisomy 18/13 algorithm and 56.4 % with the trisomy 21 algorithm. The respective false-positive rates were 0.7 % and 4.7 %. The combination of the trisomy 18/13 and the trisomy 21 algorithm with the same cut-offs led to a detection rate of 94.9 % at an overall false-positive rate of 5.0 %.
Despite a substantial underestimation of the fetal NT, the combined use of the trisomy 18/13 and the trisomy 21 algorithm of the FMF London leads to a detection rate for trisomy 18/13 of about 95 % for a false-positive rate of 5.0 %.
联合使用21、18和13三体风险算法评估孕早期18和13三体综合征的联合筛查。
对39004例妊娠进行基于孕妇年龄、孕周、胎儿颈部透明带厚度（NT）、妊娠相关血浆蛋白A（PAPP-A）和游离β人绒毛膜促性腺激素（β-hCG）的孕早期联合筛查。根据当前的早孕期联合筛查伦敦算法计算21、18、13三体综合征的个体特异性风险。
研究人群包括38751例单胎妊娠，其中39例为18或13三体综合征。在非整倍体组中，NT中位数差值为0.72mm，PAPP-A为0.21倍中位数（MoM），游离β-hCG为0.33MoM。虽然18或13三体胎儿的NT测量值只有41%高于第95百分位数，但18/13三体综合征算法对18或13三体综合征的检出率为82%，21三体综合征算法的检出率为56.4%。各自的假阳性率分别为0.7%和4.7%。18/13三体综合征算法和21三体综合征算法采用相同的截断值联合使用，总体假阳性率为5.0%时，检出率为94.9%。
尽管胎儿NT被大幅低估，但联合使用早孕期联合筛查伦敦的18/13三体综合征算法和21三体综合征算法，在假阳性率为5.0%时，18/13三体综合征的检出率约为95%。
