Infectious Diseases Unit, Ziv Medical Center and Tel-Hai Academic Collage, Tel-Hai, Israel.
Clinical Microbiology Laboratory, Ziv Medical Center and Tel-Hai Academic Collage, Tel-Hai, Israel.
Infection. 2022 Aug;50(4):959-963. doi: 10.1007/s15010-022-01772-4. Epub 2022 Feb 17.
Since 2020, a SARS-COV2 epidemic has been raging worldwide. The cycle of the PCR test in which the virus is detected is called cycle threshold (CT). The method of obtaining the sample is not detailed in any published study and is based on general guidelines of the CDC. Our contention is that the manner in which the sample is obtained has a dramatic effect on CT values.
For each person suspected of having Covid-19 who arrives at the emergency room, two swabs are taken in succession, one according to CDC guidelines and the other according to "Ziv" guidelines. The Ziv method sample collection guidelines determine the depth of penetration, the number of rotations of the swab, and their direction. Each double sample was sent for analysis.
Analysis of the CT results of the sample to results methods and of the Seegene platform clearly found (p = 0.003 and p = 0.001, respectively) that more rigorous sample collection yielded lower CT values.
The method of obtaining the samples had a dramatic effect on CT results. Any publication that includes CT results, and certainly studies that discuss CT kinetics, must describe in detail the method by which the samples were obtained. In places where it is also important to detect the onset of illness (airports, hospitals, schools, etc.), it is important to use the Ziv method to reduce the risk of false negatives.
自 2020 年以来，SARS-COV2 疫情在全球范围内肆虐。检测病毒的 PCR 测试的循环称为循环阈值（CT）。获取样本的方法在任何已发表的研究中都没有详细说明，而是基于 CDC 的一般指南。我们认为，获取样本的方式对 CT 值有显著影响。
对于每个因怀疑患有 Covid-19 而到达急诊室的人，我们会连续采集两个拭子，一个按照 CDC 指南，另一个按照“Ziv”指南。Ziv 方法样本采集指南确定了穿透深度、拭子旋转的次数及其方向。每个双份样本都被送去分析。
对样本采集方法和 Seegene 平台的 CT 结果进行分析，结果表明（分别为 p=0.003 和 p=0.001），更严格的样本采集方法会产生更低的 CT 值。
获取样本的方法对 CT 结果有显著影响。任何包含 CT 结果的出版物，当然还有讨论 CT 动力学的研究，都必须详细描述获取样本的方法。在需要检测疾病发作的地方（机场、医院、学校等），使用 Ziv 方法降低假阴性的风险非常重要。
