Rao Sonia N, Manissero Davide, Steele Victoria R, Pareja Josep
QIAGEN Inc, Germantown, MD, USA.
QIAGEN Manchester Ltd, Manchester, UK.
Infect Dis Ther. 2020 Sep;9(3):573-586. doi: 10.1007/s40121-020-00324-3. Epub 2020 Jul 28.
The ability to predict likely prognosis and infectiousness for patients with COVID-19 would aid patient management decisions. Diagnosis is usually via real-time PCR, and it is unclear whether the semi-quantitative capability of this method, determining viral load through cycle threshold (Ct) values, can be leveraged.
We aim to review available knowledge on correlations between SARS-COV-2 Ct values and patient- or healthcare-related outcomes to determine whether Ct values provide useful clinical information.
A PubMed search was conducted on 1 June 2020 based on a search strategy of (Ct value OR viral load) AND SARS-CoV-2. Data were extracted from studies reporting on the presence or absence of an association between Ct values, or viral loads determined via Ct value, and clinical outcomes.
Data from 18 studies were relevant for inclusion. One study reported on the correlation between Ct values and mortality and one study reported on the correlation between Ct values and progression to severe disease; both reported a significant association (p < 0.001 and p = 0.008, respectively). Fourteen studies reported on the correlation between Ct value or viral loads determined via Ct value and disease severity, and an association was observed in eight (57%) studies. Studies reporting on the correlation of viral load with biochemical and haematological markers showed an association with at least one marker, including increased lactate dehydrogenase (n = 4), decreased lymphocytes (n = 3) and increased high-sensitivity troponin I (n = 2). Two studies reporting on the correlation with infectivity showed that lower Ct values were associated with higher viral culture positivity.
Data suggest that lower Ct values may be associated with worse outcomes and that Ct values may be useful in predicting the clinical course and prognosis of patients with COVID-19; however, further studies are warranted to confirm clinical value.
预测新型冠状病毒肺炎（COVID-19）患者的可能预后及传染性，将有助于做出患者管理决策。诊断通常通过实时聚合酶链反应（PCR）进行，目前尚不清楚该方法通过循环阈值（Ct）值确定病毒载量的半定量能力是否可用。
我们旨在回顾关于严重急性呼吸综合征冠状病毒2（SARS-CoV-2）Ct值与患者或医疗相关结局之间相关性的现有知识，以确定Ct值是否能提供有用的临床信息。
2020年6月1日，基于（Ct值或病毒载量）与SARS-CoV-2的检索策略，在PubMed上进行了检索。数据从报告Ct值或通过Ct值确定的病毒载量与临床结局之间是否存在关联的研究中提取。
18项研究的数据符合纳入标准。一项研究报告了Ct值与死亡率之间的相关性，另一项研究报告了Ct值与进展为重症疾病之间的相关性；两项研究均报告了显著相关性（分别为p<0.001和p=0.008）。14项研究报告了Ct值或通过Ct值确定的病毒载量与疾病严重程度之间的相关性，其中8项（57%）研究观察到了相关性。报告病毒载量与生化和血液学标志物相关性的研究显示与至少一种标志物存在关联，包括乳酸脱氢酶升高（n=4）、淋巴细胞减少（n=3）和高敏肌钙蛋白I升高（n=2）。两项报告与传染性相关性的研究表明，较低的Ct值与较高的病毒培养阳性率相关。
数据表明，较低的Ct值可能与更差的结局相关，且Ct值可能有助于预测COVID-19患者的临床病程和预后；然而，需要进一步研究以证实其临床价值。
