摘要目的:评估病毒载量对严重急性呼吸综合征冠状病毒2型（severe acute respiratory syndrome coronavirus 2，SARS-CoV-2）全基因组测序准确性的影响，为新冠病毒基因监测提供技术支撑。方法:提取3例新冠病毒阳性病例的核酸进行4个梯度稀释处理，同时提取83例新冠病毒阳性病例的核酸进行验证，通过测序深度、基因组覆盖率和测序深度均一性等指标对测序结果进行评价。结果:病毒载量的改变不能影响原始测序数据的质量，病毒载量对测序数据的准确性具有一定的影响：当Ct值≤32时，病毒载量变化对测序深度和基因组覆盖率的影响并不显著，能够达到全基因组测序目的；当Ct达到38时，覆盖率急剧下降至50%以下，无法测到病毒的基因组全长。结论:通过评估病毒载量对SARS-CoV-2的测序准确性的影响，我们建议选取Ct值≤32的样本，产生的测序数据的全基因组覆盖率能够满足后续分析要求。

abstractsObjective:To evaluate the impact of viral load on the accuracy of the whole-genome sequencing of SARS-CoV-2, so as to provide technical guidance for the surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes in Beijing.Methods:The nucleic acid from three COVID-19 positive were extracted and diluted into four viral load gradients. The samples from 83 COVID-19 positive cases carrying different viral loads were extracted for viral nucleic acid. All prepared samples were sequenced by high throughput sequencing. The sequencing depth, genome coverage and homogeneity of sequencing depth were used to evaluate the sequencing results.Results:The alteration of viral loads showed no effect on the quality of raw data but affect accuracy of sequencing data to certain extend. If the Ct value was ≤32, there was no significant impact on sequencing depth and coverage rate, and the purpose of whole-genome sequencing could be achieved. In case of Ct value reached 38, the sequencing coverage rate dropped sharply to below 50%, and the whole-genome sequencing of SARS-CoV-2 could not be obtained.Conclusions:Based on the evaluation the influence of viral load on the sequencing accuracy of SARS-CoV-2, it is recommend that using samples with Ct value ≤32 could generated sequencing data with high genome coverage and sufficient for further analysis.