Department of Pathology and Laboratory Medicine, Women & Infants Hospital, Providence, RI, USA.
Department of Pathology and Laboratory Medicine, Alpert Medical School at Brown University, Providence, RI, USA.
Clin Chem. 2022 Nov 3;68(11):1449-1458. doi: 10.1093/clinchem/hvac131.
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.
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.
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.
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.
通过游离（cfDNA）进行常见三体的产前筛查通常采用大规模平行测序、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。另一种简单且不那么复杂的方法是利用滚环扩增（RCA）。有必要进一步评估其性能和相关要求。
在 16 个地点，妊娠 10 至 20 周的孕妇在知情同意的情况下提供了相关信息和 2 至 3 份血样。运送用于检测的样本进行处理和储存。孕妇在初次 cfDNA 筛查时或在转诊进行诊断性检测时入组。RCA 检测在入组后 11 个月进行。诊断结果和分娩记录确定了临床事实。检测率基于确诊的三体妊娠；假阳性率基于普通人群中未受影响的妊娠。
常见三体的检测率为 95.9%（117/122，95%CI，90.5%-98.5%）；总假阳性率为 1.00%（22/2,205，0.65%-1.51%）。重复检测后检测失败率为 0.04%。当检测标准偏差低于预定水平时，总假阳性率低至 0.30%（P<0.001）。胎儿性别检测准确率为 99.7%。一名技术员在两周内分析了 560 个样本，每年分析 14 000 个样本。
我们对在产前筛查实验室进行的常见三体产前筛查的简化 cfDNA 检测系统的评估结果令人鼓舞。通过收集 2 个样本可以实现更高的检测率、更低的检测失败率和快速报告。未来的重点应该是通过使用单个收集管来提高运行精度。
NCT03087357。
