From the Molecular & Genomic Pathology Laboratory, Clinical Laboratories, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (Jin, Hartnett).
the Departments of Pathology, Anatomy, & Cell Biology (Pettengill, Peiper, Wang) and Surgery (Wang), Thomas Jefferson University, Philadelphia, Pennsylvania.
Arch Pathol Lab Med. 2020 Nov 1;144(11):1303-1310. doi: 10.5858/arpa.2020-0283-SA.
CONTEXT.—: We implemented multiple nucleic acid amplification test platforms because of the limited availability of test kits for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during the early stages of the pandemic. Interpretation of results generated by different platforms and prioritization for testing algorithms required cross-comparison.
OBJECTIVE.—: To compare the analytical sensitivity of 3 commercial SARS-CoV-2 molecular assays, selected samples were studied in parallel with Cobas SARS-CoV-2 test, NxTAG CoV Extended Panel, and ID NOW COVID-19 assays.
DESIGN.—: A total of 8043 SARS-CoV-2 tests performed from March 22 to April 19, 2020, were included in this study. For all 1794 positive specimens detected by the cobas SARS-CoV-2 assay, the cycle threshold (Ct) values were manually tracked and plotted to demonstrate the distribution of sample viral levels. Additionally, 50 and 63 low-positive specimens (Ct values >32) as well as 50 and 61 consecutive positive specimens by the cobas assay were tested with NxTAG and ID NOW, respectively, to estimate their relative sensitivities.
RESULTS.—: The Ct values of cobas SARS-CoV-2-positive samples were evenly distributed throughout ranges of 13.32 to 39.50 (mean, 25.06) and 13.60 to 42.49 (mean, 26.45) for ORF1 and E gene targets, respectively. NxTAG reliably detected only specimens with E gene Ct values lower than 33, and is estimated to detect 89.4% of positive specimens detected by cobas assay. ID NOW had performance variation independent of Ct value and is estimated to detect 83.5% of cobas positives.
CONCLUSIONS.—: Clinical specimens exhibit a wide range of viral burden, with a significant portion at low levels. Analytical sensitivity of testing platforms is critical for reliable detection of SARS-CoV-2 and uniform care to patients.
在大流行早期，由于严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）检测试剂盒的供应有限，我们实施了多种核酸扩增检测平台。不同平台产生的结果的解释和检测算法的优先级需要进行交叉比较。
比较 3 种商业 SARS-CoV-2 分子检测方法的分析灵敏度，选择部分样本与 Cobas SARS-CoV-2 检测、NxTAG CoV 扩展面板和 ID NOW COVID-19 检测同时进行研究。
共纳入了 2020 年 3 月 22 日至 4 月 19 日期间进行的 8043 项 SARS-CoV-2 检测。对于 Cobas SARS-CoV-2 检测检出的 1794 份阳性标本，手动跟踪并绘制 Ct 值，以展示样本病毒水平的分布。此外，用 NxTAG 和 ID NOW 检测了 50 份和 63 份低阳性（Ct 值>32）标本以及 50 份和 61 份连续 Cobas 阳性标本，以估计它们的相对灵敏度。
Cobas SARS-CoV-2 阳性样本的 Ct 值均匀分布在 ORF1 和 E 基因靶标分别为 13.32 到 39.50（平均值 25.06）和 13.60 到 42.49（平均值 26.45）的范围内。NxTAG 仅可靠地检测到 E 基因 Ct 值低于 33 的标本，估计能检测到 Cobas 检测法检出的 89.4%阳性标本。ID NOW 的检测性能与 Ct 值无关，估计能检测到 Cobas 检测法检出的 83.5%阳性标本。
临床标本的病毒载量范围很广，其中相当一部分处于低水平。检测平台的分析灵敏度对于可靠检测 SARS-CoV-2 和为患者提供统一的护理至关重要。
