Department of Hematology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China; Aid Hubei Medical Team, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China.
Department of Neurology Intensive Care Unit, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China; Aid Hubei Medical Team, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China.
Clin Chim Acta. 2020 Dec;511:291-297. doi: 10.1016/j.cca.2020.10.019. Epub 2020 Oct 21.
Repositivity of SARS-CoV-2 nucleic acid in discharged COVID-19 patients was reported recently. However, the characteristics of repositive results are still not well understood, leading to a lack of effective monitoring strategies.
In the present study, a total of 59 COVID-19 patients were enrolled, and the characteristics of the repositive samples were analyzed.
The repositive rate in this cohort was 15.79%. The N gene was the main target gene that was positive in the repositive results as well as in the last positive results of all patients. The median duration from diagnosis to the last positive test was 20 days (IQR, 16-31 days), and the longest duration was 40 days. Repositivity was only observed in IgM single- or both IgM- and IgG-positive patients, instead of IgG single-positive patients.
There was a significant proportion of repositives in the recovered COVID-19 patients, and increasing the required number of negatives for consecutive nucleic acid tests may reduce the incidence of repositives. The recommended monitoring strategy for repositivity is monitoring the N gene in IgM-positive patients. This can ensure high sensitivity while reducing the time and cost of nucleic acid detection.
最近有报道称，出院的 COVID-19 患者的 SARS-CoV-2 核酸再次阳性。然而，对于复阳结果的特征尚不完全清楚，导致缺乏有效的监测策略。
本研究共纳入 59 例 COVID-19 患者，分析复阳样本的特征。
本队列的复阳率为 15.79%。N 基因是复阳结果以及所有患者最后一次阳性结果中的主要靶基因。从诊断到最后一次阳性检测的中位时间为 20 天（IQR，16-31 天），最长时间为 40 天。复阳仅发生在 IgM 单项或 IgM 和 IgG 双项阳性患者中，而 IgG 单项阳性患者未发生复阳。
在已康复的 COVID-19 患者中，存在相当比例的复阳患者，增加连续核酸检测所需的阴性结果数量可能会降低复阳的发生率。建议对复阳进行监测的策略是监测 IgM 阳性患者的 N 基因。这可以确保高灵敏度，同时减少核酸检测的时间和成本。
