Diagnostic value and dynamic variance of serum antibody in coronavirus disease 2019

Int J Infect Dis. 2020 May;94:49-52. doi: 10.1016/j.ijid.2020.03.065. Epub 2020 Apr 3.

Abstract

Objective: To investigate the diagnostic value of serological testing and dynamic variance of serum antibody in coronavirus disease 2019 (COVID-19).

Methods: This study retrospectively included 43 patients with a laboratory-confirmed infection and 33 patients with a suspected infection, in whom the disease was eventually excluded. The IgM/IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was measured by chemiluminescence immunoassay analysis.

Results: Compared to molecular detection, the sensitivities of serum IgM and IgG antibodies to diagnose COVID-19 were 48.1% and 88.9%, and the specificities were 100% and 90.9%, respectively.In the COVID-19 group, the IgM-positive rate increased slightly at first and then decreased over time; in contrast, the IgG-positive rate increased to 100% and was higher than IgM at all times. The IgM-positive rate and titer were not significantly different before and after conversion to virus-negative. The IgG-positive rate was up to 90% and not significantly different before and after conversion to virus-negative. However, the median IgG titer after conversion to virus-negative was double that before, and the difference was significant.

Conclusions: Viral serological testing is an effective means of diagnosis for SARS-CoV-2 infection. The positive rate and titer variance of IgG are higher than those of IgM in COVID-19.

Keywords: COVID-19; Diagnosis; Immunoglobulin G; Immunoglobulin M; SARS-CoV-2; Serological test.

MeSH terms

  • Betacoronavirus / immunology*
  • Coronavirus Infections / diagnosis*
  • Female
  • Humans
  • Immunoglobulin G / blood*
  • Immunoglobulin M / blood*
  • Male
  • Middle Aged
  • Pandemics
  • Pneumonia, Viral / diagnosis*
  • Retrospective Studies
  • Serologic Tests

Substances

  • Immunoglobulin G
  • Immunoglobulin M

Supplementary concepts

  • COVID-19
  • severe acute respiratory syndrome coronavirus 2