探讨含胍盐病毒灭活保存管对提高2019新型冠状病毒核酸检测安全性和准确性的作用。

以2020年2月广州市妇女儿童医疗中心4例确诊患儿的10份经本院新型冠状病毒核酸检测结果为阳性的标本作为研究对象，分别使用含胍盐灭活保存管和某品牌病原运送管的保存液洗脱后分装，在室温条件下分别放置12 h、24 h和48 h，然后转至-80℃冰箱保存至检测。比较两组样本qPCR结果，并进行统计学分析。

同样病毒量放入两种不同的取材管处理，立即进行qPCR，含胍盐的灭活管核酸检出量更高。在病毒高载量标本中，两种取材管在不同时间段的检测结果相关性较高，灭活保存管的CT值更小，室温放置24 h后，结果差异均具有统计学意义（P<0.05）；在病毒载量中等的标本中，两种取材的测量结果差异不具有统计学意义（P>0.05），但测量结果均随时间变化而变化，病毒灭活保存管组扩增曲线更早出现，CT值更小；当检测病毒低载量样本时，两组扩增结果有较大的差异（24 h后P<0.01），灭活保存管在放置时间24 h内均能检测出阳性结果，而病原运送管结果不稳定，仅在较短放置时间内能够检测出阳性结果。灭活保存管组的检出率要比病原运送管组的高，三个基因靶点检测的重复性更好，显示具有更强的病毒核酸的保存能力。

在冠状病毒核酸检测采样时，使用含胍盐的病毒灭活保存取材管，一方面可以在取材后立即灭活病毒，大大降低实验室暴露感染的危险，并能实现样本的室温保存和运输，减低转运成本，利于基层单位的送检，另一方面，能维持病毒核酸的稳定性，使低拷贝数的病毒更容易被检出，减少假阴性，对保证新型冠状病毒核酸检测的准确性有积极意义。

To explore the role of guanidine salt-containing virus inactivated storage tubes in improving the safety and accuracy of COVID-19 nucleic acid assay.

Ten samples that were positive for nucleic acid of 4 COVID-19 cases diagnosed in Guangzhou Women and Children's Medical Center in February, 2020 were studied. The samples were eluted and aliquoted using the storage solution of guanidine salt--containing inactivated storage tube and a certain brand of pathogen delivery tube, and then stored at room temperature for 12 h, 24 h and 48 h, respectively and transfered to the refrigerator at -80 ℃ before testing. The results of qPCR were compared between the two groups, and the differences were statistically analyzed.

The same amount of virus was put into two different sampling tubes and immediately subjected to qPCR, with higher detection of nucleic acid in inactivated tubes containing guanidine salt. In the high viral load samples, the correlation between the detection results of the two types of tubes at different time periods was higher. The CT values of the inactivated storage tubes were smaller, and the results are statistically significant (P<0.05) after 24 h at room temperature. In the samples with medium viral load, the measurement results of the two kinds of sampling tubes are not statistically significant (P>0.05), but the measured results varied with time, and the amplification curve of inactivated storage tube group appeared earlier and the CT values were smaller. When detecting the low viral load samples, there was a large difference (P<0.01 after 24 h) between the amplification results of the two groups and the inactivated tubes were able to obtain positive results within 24 h of placement time, while the results of pathogen delivery tubes were unstable and only within a short storage time could they obtain the positive results. The detection rate of inactivated storage tube group was higher than that of pathogen delivery tube group, with better reproducibility of the target three gene assays, indicating a stronger ability of viral nucleic acid.

In the COVID-19 nucleic acid sampling process, the use of virus inactivation storge tubes containing guanidine salt, on the one hand, can immediately inactivate the virus after sampling, greatly reduce the risk of laboratory exposure to infection and can achieve room temperature preservation and transportation of samples, reduce the cost of transshipment, conducive to the delivery of the grassroots unit. On the other hand, it can maintain the stability of viral nucleic acid, make it easier to detect low copy number viruses, and reduce false negatives which has a positive significance for ensuring the accuracy of COVID-19 nucleic acid detection.