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Serological testing for COVID-19 

Journal of Lung, Pulmonary & Respiratory Research
Attapon Cheepsattayakorn,1 Ruangrong Cheepsattayakorn2

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The objectives of this study are to identify the rapid, appropriate, screening, definite and novel methods of diagnosis of SARS-CoV-2 (COVID-19) infection, including SARSCoV-2 (COVID-19) variants among various degree of COVID-19 severity for rapid prevention and control of SARS-CoV-2 (COVID-19) transmission. Methods of The Study: A comprehensive search was carried out in mainstream bibliographic databases or Medical Subject Headings, including ScienDirect, PubMed, Scopus, and ISI Web of Science. The search was applied to the articles that were published between 1971 and early March 2021. Results: With strict literature search and screening processes, it yielded 40 articles from 78 articles of initial literature database.

Characteristically, after infection, antibodies are detected in the blood of individuals, particularly individuals with few or mild symptoms. In patients with varying symptoms of COVID-19 and negative results of reverse-transcriptase-polymerase-chain reaction (RT-PCR) tests, the testing has a significantly clinical role when nasopharyngeal swabs are taken more than 5 days after symptom onset. The Royal College of Pathologists (RCPath) developed seven principles for production of a COVID-19 testing strategy. Testing being carried out for a purpose is one of these RCPath’s principles. Nevertheless, denial of requesting SARS-CoV-2 (COVID-19) antibody tests for reassurance should be cautioned. With a lower antibody levels, whether the protective immunity will be sustained is questionable. Several immune-based assays were developed against different SARS-CoV-2 (COVID-19) viral proteins as the followings: 1) Entire Spike (S) protein, IgG antibody from patient serum can cross-react with SARS-CoV and MERS-CoV, 2) S1 subunit of Spike (S) protein, IgA, IgG antibodies from patient serum can cross-react with SARS-CoV only, 3) Receptor-binding domain (RBD), IgG antibody from patient serum can cross-react with SARS-CoV only, and 4) Nucleocapsid (N), IgG antibody from patient serum can cross-react with SARS-CoV only. Long et al demonstrated in their study that IgG antibody and neutralizing antibody levels initiate decreasing within 2-3 months after infection in the majority of persons with recovery from SARS-CoV-2 (COVID-19) infection. An analytical study of the dynamics of neutralizing antibody titers demonstrated reduced neutralizing antibodies around 6-7 weeks after illness onset. In conclusion, the nucleic acid amplification tests may be poorly timed specimen collection, poor-quality specimen collection, long wait times for generating the results, and requirement of trained laboratory technicians. Serological data greatly supplement the laboratory results from the quantitative reverse-transcriptase-polymerase-chain reaction (qRT-PCR), the design of virus elimination programs (seroepidemiology), discovery of the monoclonal antibodies, and development of SARS-CoV-2 (COVID-19) vaccines.  


COVID-19, SARS-CoV-2, serological test, polymerase chain reaction, molecular diagnostics, variants, severe illnesses, complications