National Reference Centre for Respiratory Pathogens, Department of Laboratory Medicine, University Hospitals Leuven, 3000 Leuven, Belgium.
Epidemiology of Infectious Diseases and Quality Service Unit, Scientific Directorate of Epidemiology and Public Health, Sciensano, 1000 Brussels, Belgium.
Viruses. 2022 Jun 14;14(6):1294. doi: 10.3390/v14061294.
From early 2020, a high demand for SARS-CoV-2 tests was driven by several testing indications, including asymptomatic cases, resulting in the massive roll-out of PCR assays to combat the pandemic. Considering the dynamic of viral shedding during the course of infection, the demand to report cycle threshold (Ct) values rapidly emerged. As Ct values can be affected by a number of factors, we considered that harmonization of semi-quantitative PCR results across laboratories would avoid potential divergent interpretations, particularly in the absence of clinical or serological information. A proposal to harmonize reporting of test results was drafted by the National Reference Centre (NRC) UZ/KU Leuven, distinguishing four categories of positivity based on RNA copies/mL. Pre-quantified control material was shipped to 124 laboratories with instructions to setup a standard curve to define thresholds per assay. For each assay, the mean Ct value and corresponding standard deviation was calculated per target gene, for the three concentrations (10, 10 and 10 copies/mL) that determine the classification. The results of 17 assays are summarized. This harmonization effort allowed to ensure that all Belgian laboratories would report positive PCR results in the same semi-quantitative manner to clinicians and to the national database which feeds contact tracing interventions.
自 2020 年初以来，由于包括无症状病例在内的多种检测指征对 SARS-CoV-2 检测的需求较高，因此大规模推出了 PCR 检测来对抗这一流行病。考虑到感染过程中病毒脱落的动态变化，对快速报告循环阈值（Ct）值的需求迅速出现。由于 Ct 值可能受到许多因素的影响，我们认为跨实验室协调半定量 PCR 结果可以避免潜在的不同解释，特别是在缺乏临床或血清学信息的情况下。由 UZ/KU Leuven 的国家参考中心（NRC）起草了一份协调检测结果报告的提案，根据 RNA 拷贝数/mL 将结果分为四个阳性类别。预定量的对照材料被运送到 124 个实验室，并附有根据每个检测方法设置标准曲线的说明。对于每个检测方法，针对确定分类的三个浓度（10、10 和 10 拷贝/mL）计算每个靶基因的平均 Ct 值和相应的标准偏差。总结了 17 种检测方法的结果。这一协调工作确保了所有比利时实验室将以相同的半定量方式向临床医生和国家数据库报告阳性 PCR 结果，该数据库为接触者追踪干预提供信息。
