Background Prenatal screening for common trisomies via cell-free (cfDNA) is usually implemented by technologies utilizing massively parallel sequencing, stringent environmental controls, complex bioinformatics, and molecular expertise. An alternative and less complex methodology utilizes rolling circle amplification (RCA). Further evaluation of its performance and related requirements are warranted. Methods At 16 sites, women at 10 to 20 weeks gestation provided informed consent, relevant information, and 2 to 3 blood samples. Samples shipped for testing were processed and stored. Women were enrolled at primary cfDNA screening, or following such screening at referral for diagnostic testing. RCA testing occurred post-enrollment, over 11 months. Diagnostic results and delivery notes determined clinical truth. Detection rates were based on confirmed trisomic pregnancies; false-positive rates were based on unaffected pregnancies from the general population. Results Detection rate for the common trisomies was 95.9% (117/122, 95% CI, 90.5%–98.5%); overall false-positive rate was 1.00% (22/2,205, 0.65%–1.51%). Test failure rate after repeat testing was 0.04%. When assay standard deviations were below pre-specified levels, the overall false-positive rate was much lower at 0.30% (P < 0.001). Fetal sex calls were correct for 99.7%. One technician analyzed 560 samples over 2 weeks, a rate of 14 000/year. Conclusions Our assessment of this simplified cfDNA-based system for prenatal screening for common trisomies performed in a prenatal screening laboratory is encouraging. Improved detection, low failure rates and rapid reporting can be achieved by collecting 2 samples. Future priorities should include achieving higher run precision using a single collection tube. Clinicaltrials.gov Registration Number: NCT03087357.

中文翻译：

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用于产前唐氏综合症筛查的简化无细胞 DNA 方法的评估

背景 通过无细胞 (cfDNA) 对常见三体性进行产前筛查通常是通过利用大规模平行测序、严格的环境控制、复杂的生物信息学和分子专业知识的技术来实施的。另一种不太复杂的方法是使用滚环扩增 (RCA)。有必要对其性能和相关要求进行进一步评估。方法在16个地点，妊娠10至20周的妇女提供了知情同意书、相关信息和2至3份血样。运送用于测试的样品经过处理和储存。女性被纳入初级 cfDNA 筛查，或在转诊进行诊断测试时接受此类筛查。RCA 测试发生在注册后，超过 11 个月。诊断结果和送货单决定了临床真相。检出率基于确认的三体妊娠；假阳性率基于普通人群未受影响的怀孕。结果常见三体检出率为95.9%（117/122，95% CI，90.5%～98.5%）；总体假阳性率为 1.00% (22/2,205, 0.65%–1.51%)。重复测试后的测试失败率为 0.04%。当测定标准偏差低于预先指定的水平时，总体假阳性率低得多，为 0.30% (P < 0.001)。胎儿性呼叫正确率为 99.7%。一名技术人员在 2 周内分析了 560 个样本，分析率为每年 14000 个。结论 我们对这种在产前筛查实验室进行的用于常见三体性产前筛查的简化的基于 cfDNA 的系统的评估令人鼓舞。改进检测，通过收集 2 个样本可以实现低故障率和快速报告。未来的优先事项应包括使用单个收集管实现更高的运行精度。Clinicaltrials.gov 注册号：NCT03087357。