Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Dec;9(1):1974-1983.
doi: 10.1080/22221751.2020.1810133.

Dynamic changes of throat swabs RNA and serum antibodies for SARS-CoV-2 and their diagnostic performances in patients with COVID-19

Xueping Qiu  1 , Yang Xiang  1 , Jianbin Sun  2 , Xinrui Wang  3 , Guoqiang Chen  4 , Xianqun Xu  1 , Shengjun Liao  1 , Na Yang  1 , Siwei Li  1 , Gang Yang  1 , Yueting Tang  1 , Junli Fan  1 , Wen Xie  1 , Hanning Hu  1 , Yirong Li  1 , Fang Zheng  1
Affiliations

Dynamic changes of throat swabs RNA and serum antibodies for SARS-CoV-2 and their diagnostic performances in patients with COVID-19

Xueping Qiu et al. Emerg Microbes Infect. 2020 Dec.

Abstract

Dynamic changes of RNA and antibodies in SARS-CoV-2 infected patients remain largely unknown, and influence factors for antibody production have not been fully clarified. In this study, consecutive throat swabs specimens (n = 1875) from 187 patients were collected to analyse the dynamic changes of RNA. Moreover, 162 serial serum samples from 31 patients were tested for seroconversion of IgM and IgG. Meanwhile, IgM and IgG were also detected in 409 COVID-19 patients and 389 controls. Additionally, the logistic regression analysis was executed to identify the possible influence factors for antibody production. The median positive conversion time for RNA was day 7 (IQR, 3-11), and the positive rate was highest in day 1-5 (74.59 %) and then gradually decreased. The median time of seroconversion for IgM and IgG were both day 12 (IQR, 10-15). The sensitivity and specificity for IgM (or IgG) was 87.04% and 96.92%, respectively. Multivariate logistic regression indicated that reduced lymphocytes and short positive conversion time for SARS-CoV-2 RNA were independent factors for negative results of IgM and IgG. In conclusion, RNA and antibodies should be combined for COVID-19 diagnosis, and delayed seroconversion was influenced by the decreased lymphocytes and short positive conversion time for RNA.

Keywords: Antibody; COVID-19; RNA; SARS-CoV-2; throat swabs.

PubMed Disclaimer

Conflict of interest statement

No potential conflict of interest was reported by the author(s).

Figures

Figure 1.
Figure 1.
The positive rates of RNA and antibodies among COVID-19 patients in different time durations since symptoms onset. The positive rate of RNA was analysed in 1875 throat swab specimens from 187 COVID-19 confirmed patients. The positive rate of antibodies was analysed in 409 serum samples from 409 COVID-19 confirmed patients.
Figure 2.
Figure 2.
Positive conversion of RNA and antibodies against SARS-CoV-2 in COVID-19 patients. Cumulative positive rates of patients with COVID-19 for RNA and antibody (IgM, IgG) were displayed by courses of the disease. The scale on the right of the figure shows the positive rate level indicated with different colours, the blue corresponds to a low positive rate and the red to a high positive rate. The lower table presents the number of samples that tested positive at each time point.
Figure 3.
Figure 3.
The longitudinal changes of antibody and RNA in 10 representative patients with COVID-19. The red solid square represents the positive result of RNA, the green solid square represents the negative result of RNA, and the black solid square represents no sample was collected.
Figure 4.
Figure 4.
Lymphocyte counts in different subtypes of COVID-19 patients. Independent-samples t test was used to comparison the variables in different groups. * p < 0.05, ** p < 0.01, **** p < 0.0001.
See this image and copyright information in PMC

References

    1. WHO . Coronavirus disease (COVID-19) Situation Report-108 [7 May 2020]. Available from: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/situatio....
    1. Cui J, Li F, Shi ZL.. Origin and evolution of pathogenic coronaviruses. Nat Rev Microbiol. 2019 Mar;17(3):181–192. doi: 10.1038/s41579-018-0118-9 - DOI - PMC - PubMed
    1. National Health Commission of the People’s Republic of China . The Guidelines for Diagnosis and Treatment of Novel Coronavirus Pneumonia (7th version): National Health Commission of China; [7 May 2020]. Available from: http://www.nhc.gov.cn/yzygj/s7653p/202003/46c9294a7dfe4cef80dc7f5912eb19....
    1. Zhang W, Du RH, Li B, et al. Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes. Emerg Microbes Infect. 2020;9(1):386–389. doi: 10.1080/22221751.2020.1729071 - DOI - PMC - PubMed
    1. Liu R, Han H, Liu F, et al. Positive rate of RT-PCR detection of SARS-CoV-2 infection in 4880 cases from one hospital in Wuhan, China, from Jan to Feb 2020. Clin Chim Acta. 2020 Jun;505:172–175. doi: 10.1016/j.cca.2020.03.009 - DOI - PMC - PubMed

MeSH terms