Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients
Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients
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DOI：
10.1093/ajcp/aqaa133
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发表时间：
2020-10-01
影响因子：
3.5
通讯作者：
Ledeboer, Nathan A.
中科院分区：
文献类型：
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作者：
Buchan, Blake W.;Hoff, Jessica S.;Ledeboer, Nathan A.
目的：我们检查了从接受2019冠状病毒病（COVID-19）评估的有症状患者中获得的逆转录聚合酶链反应（RT-PCR）循环阈值（CT）值的分布，以确定含有接近检测限（LoD）的病毒载量的标本比例，从而实际了解假阴性结果的风险。我们还研究了CT值和患者年龄之间的关系，以确定任何年龄依赖性差异的病毒载量或测试sensitivity.Methods：我们收集的CT值从cobas严重急性呼吸综合征冠状病毒2（SARS-CoV-2）检测相应的1,213合并鼻咽口咽标本从症状的个人，被报道为阳性或推定阳性的SARS-CoV-2。CT值按SARS-CoV目标和患者年龄组分层。结果：总共有93.3%至98.4%的标本显示CT值大于3倍检测LoD，此时假阴性结果将不会出现。年龄组之间的平均CT值在统计学上相等，但80至89岁年龄组的患者除外，其CT值略低。基于观察到的CT值的分布，包括数值接近检测LoD的样本的小部分，从有症状个体中获得的鼻咽-口咽合并样本中假阴性RT-PCR结果的风险较低。
Objectives: We examined the distribution of reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (CT) values obtained from symptomatic patients being evaluated for coronavirus disease 2019 (COVID-19) to determine the proportion of specimens containing a viral load near the assay limit of detection (LoD) to gain practical insight to the risk of false-negative results. We also examined the relationship between CT value and patient age to determine any age-dependent difference in viral load or test sensitivity.Methods: We collected CT values obtained from the cobas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay corresponding to 1,213 combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals that were reported as positive or presumptive positive for SARS-CoV-2. CT values were stratified by SARS-CoV target and patient age group.Results: In total, 93.3% to 98.4% of specimens demonstrated CT values greater than 3x the assay LoD, at which point false-negative results would not be expected. The mean of CT values between age groups was statistically equivalent with the exception of patients in age group 80 to 89 years, which demonstrated slightly lower CTs.Conclusions: Based on the distribution of observed CT values, including the small proportion of specimens with values near the assay LoD, there is a low risk of false-negative RT-PCR results in combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals.