Serology tests are essentials tools during this coronavirus crisis as an indicator that antibodies to SARS-CoV-2 were detected and the individual has potentially been exposed to COVID-19.
Coronaviruses cause illnesses such as the common cold, Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). In 2019, a new coronavirus was identified and named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
SARS-CoV-2 is a positive sense, single strand RNA virus belonging to the family Coronaviridae and has four structural proteins: Spike (S), Envelope (E), Membrane (M) and Nucleocapsid (N). The N-proteins hold the RNA sequence genome and the S, E, and M-proteins together create the viral envelope1. The SARS-CoV-2 spike glycoprotein is trimeric, with each 180 kDa monomer containing two subunits (S1 and S2), which facilitate the attachment and binding to the target cell2. Coronavirus disease 2019 (COVID-19) results from an infection with SARS-CoV-2. The World Health Organisation (WHO) declared COVID-19 as a pandemic in March 2020.
Elevations in specific IgM antibody levels typically occur three to five days after the onset of symptoms in response to viral infections. The presence of these antibodies generally persists for thirty to sixty days. IgG levels typically become elevated after ten to fourteen days and may remain detectable for years.
The TGS COVID-19 IgG test is a fully automated chemiluminescence immunoassay (CLIA) for the quantitative determination of specific IgG class antibodies directed against anti-SARS-CoV-2 in human serum or plasma specimens on the IDS-iSYS Multi-Discipline Automated System. For more information on the IDS-iSYS Multi-Discipline Automated System click here.
1. Li, F., Li, W., Farzan, M., & Harrison, S. (2005). Structure of SARS coronavirus spike receptor-binding domain complexed with its 10.2210/pdb2ajf/pdb 3. Ou, X., Liu, Y., Lei, X. et al. Characterization of spike glycoprotein of SARS-CoV-2 on virus entry and its immune cross-reactivity with SARS-CoV. Nat Commun 11, 1620 (2020). https://doi.org/10.1038/s41467-020-15562-9
2. Wu C, Liu Y, Yang Y, et al. Analysis of therapeutic targets for SARS-CoV-2 and discovery of potential drugs by computational methods [published online ahead of print, 2020 Feb 27]. Acta Pharm Sin B. 2020;10(5):766-788. doi:10.1016/j.apsb.2020.02.008