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. 2020 Dec;9(1):2020-2029.
doi: 10.1080/22221751.2020.1811161.

Establishing a high sensitivity detection method for SARS-CoV-2 IgM/IgG and developing a clinical application of this method

Chunyan Zhang  1 , Lei Zhou  2   3 , Hao Liu  2   3 , Sibing Zhang  1   2 , Yaping Tian  1 , Junli Huo  2   3 , Fei Li  2   3 , Yao Zhang  2   3 , Bo Wei  2   4 , Dan Xu  5 , Jinwei Hu  5 , Jiayi Wang  2   3 , Yuxuan Cheng  1 , Wenjie Shi  1 , Xiuli Xu  6 , Jianping Zhou  6 , Peipei Sang  1 , Xudong Tan  1 , Weiwei Wang  1 , Minjie Zhang  1 , Bin Wang  5 , Yujun Zhou  1 , Kan Zhang  2   3 , Kunlun He  1
Affiliations

Establishing a high sensitivity detection method for SARS-CoV-2 IgM/IgG and developing a clinical application of this method

Chunyan Zhang et al. Emerg Microbes Infect. 2020 Dec.

Abstract

COVID-19 is caused by SARS-CoV-2 infection and was initially discovered in Wuhan. This outbreak quickly spread all over China and then to more than 20 other countries. SARS-CoV-2 fluorescent microsphere immunochromatographic test strips were prepared by the combination of time-resolved fluorescence immunoassay with a lateral flow assay. The analytical performance and clinical evaluation of this testing method was done and the clinical significance of the testing method was verified. The LLOD of SARS-CoV-2 antibody IgG and IgM was 0.121U/L and 0.366U/L. The specificity of IgM and IgG strips in healthy people and in patients with non-COVID-19 disease was 94%, 96.72% and 95.50%, 99.49%, respectively; and sensitivity of IgM and IgG strips for patients during treatment and follow-up was 63.02%, 37.61% and 87.28%, 90.17%, respectively. The SARS-CoV-2 antibody test strip can provide rapid, flexible and accurate testing, and is able to meet the clinical requirement for rapid on-site testing of virus. The ability to detect IgM and IgG provided a significant benefit for the detection and prediction of clinical course with COVID-19 patients.

Keywords: SARS-CoV-2 antibody; disease evaluation; multi-epitopes fusion protein; prognosis; time-resolved fluorescence immunoassay.

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Conflict of interest statement

XXL and ZJP are employees of Beijing Diagreat Biotechnology, the commercial manufacturer of the SARS-CoV-2 IgM/IgG test strips.

Figures

Figure 1.
Figure 1.
Operation of the lateral flow immunoassay. (A) Epitope prediction of the SARS-CoV-2 N and S1 protein. (B) Fusion multi-dominant epitopes. (C) Protein expression vector. (D) Purification of the SARS-CoV-2 multi-dominant epitopes protein. (E) Schematic representation of the assay's mechanism.
Figure 2.
Figure 2.
Lowest limit of detection of the test strip for IgM (A) and IgG (B).
Figure 3.
Figure 3.
Clinical sensitivity and specificity. (A) IgM and IgG detection in healthy subjects, IgM (●) and IgG (▪). (B–C) IgM (B) and IgG (C) detection in patients with non-COVID-19 diseases.
Figure 4.
Figure 4.
IgM and IgG detection in the process of COVID-19. (A–B) Comparison of IgM (A) and IgG (B) between severe and ordinary patients. NS, nonsense; **, p < 0.01. (C) Dynamic monitoring of antibody IgG and IgM in 93 COVID-19 patients during the treatment. Sera were collected from 0 to 70 days after the onset of symptoms. IgM in the ordinary group (green circle), IgG in the ordinary group (blue square), IgM in the severe group (red circle), and IgG in severe group (pink square). The error bars correspond to 1 S.D. (D-E) Comparison of IgM (A) and IgG (B) between cured cases and death cases in severe patients. NS, nonsense; *, p < 0.05. (F) Dynamic monitoring of antibody IgG and IgM in cured cases and death cases. IgM of n cured cases (green circle), IgG of cured cases (blue square), IgM of death cases (red circle), and IgG of death cases (pink square). The error bars correspond to 1 S.D.
Figure 5.
Figure 5.
IgM and IgG levels in cured cases and death cases. (A–B) The result of the IgM (A) and IgG (B) detection in convalescent patients. Male (●), Female (○); ns, nonsense; *, p < 0.05. (C) The use of antibody detection in the suspected case screening. Cases in the red box were the monitored cases. (D) A case report.
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References

    1. Zhu N, Zhang D, Wang W, et al. . A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med. 2020 Feb 20;382(8):727–733. doi: 10.1056/NEJMoa2001017 - DOI - PMC - PubMed
    1. Xu B, Kraemer MUG, Open C-DCG.. Open access epidemiological data from the COVID-19 outbreak. Lancet Infect Dis. 2020 May;20(5):534. doi: 10.1016/S1473-3099(20)30119-5 - DOI - PMC - PubMed
    1. Sun P, Lu X, Xu C, et al. . Understanding of COVID-19 based on current evidence. J Med Virol. 2020 Jun;92(6):548–551. doi: 10.1002/jmv.25722 - DOI - PMC - PubMed
    1. Xu XW, Wu XX, Jiang XG, et al. . Clinical findings in a group of patients infected with the 2019 novel coronavirus (SARS-Cov-2) outside of Wuhan, China: retrospective case series. Br Med J. 2020 Feb 19;368:m606. doi: 10.1136/bmj.m606 - DOI - PMC - PubMed
    1. Wu YC, Chen CS, Chan YJ.. The outbreak of COVID-19: an overview. J Chin Med Assoc. 2020 Mar;83(3):217–220. doi: 10.1097/JCMA.0000000000000270 - DOI - PMC - PubMed