key: cord-0833323-hsq8b8k4
authors: Sidiq, Zeeshan; Hanif, M.; KumarDwivedi, Kaushal; Chopra, K.K.
title: Benefits and limitations of Serological Assays in COVID-19 Infection
date: 2020-08-06
journal: Indian J Tuberc
DOI: 10.1016/j.ijtb.2020.07.034
sha: 576ef6c76562385bcdc832ed567a1f94c24676a5
doc_id: 833323
cord_uid: hsq8b8k4

Accurate and rapid diagnostic tests are critical for achieving control of coronavirus disease 2019 (covid-19), a pandemic illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diagnostic tests for covid-19 fall into two main categories: molecular tests that detect viral RNA, and serological tests that detect anti-SARS-CoV-2immunoglobulins. Reverse transcriptase polymerase chain reaction (RT-PCR), a molecular test, has become the gold standard for diagnosis of covid-19; however, this test has many limitations that include potential false negative results, changes in diagnostic accuracy over the disease course, and precarious availability of test materials. Serological tests have generated substantial interest as an alternative or complement to RT-PCR and other Nucleic acid tests in the diagnosis of acute infection, as some might be cheaper and easier to implement at the point of care. A clear advantage of these tests over RT-PCR is that they can identify individuals previously infected by SARS-CoV-2, even if they never underwent testing while acutely ill. Many serological tests for covid-19 have become available in a short period, including some marketed for use as rapid, point-of-care tests. The pace of development has, however, exceeded that of rigorous evaluation, and important uncertainty about test accuracy remains.

(WHO) has declared COVID-19 a public health emergency of international concern and given a 30 "very high" risk assessment on a global level. 2

Coronavirus is positive-sense single-stranded RNA virus. It is a large pleomorphic spherical 32 enveloped particle. The viral envelope consists of a lipid bilayer where the membrane (M), 33 envelope (E), and spike (S) structural proteins are anchored. 3 The S glycoprotein is a large type 1 34 transmembrane protein consisting of two functional subunits S1 and S2. S1, comprises a 35 receptor binding domain (RBD) which is responsible for binding to the host cell receptor. S2 36 contains elements needed for the fusion of virus. 3-8 A subset of coronaviruses (in particular 37 betacoronavirus) also have a shorter spike-like surface protein called hemagglutinin esterase 38 (HE). 9 Inside the envelope there is the nucleocapsid, which is formed from multiple copies of 39 the nucleocapsid (N) protein. This protein is bound to the single-stranded RNA genome. 10 The In some patients this transit of immunity is delayed due to Individual risk factors such as older Various in-house and commercial ELISA methods have been used to validate and test different 100 SARS-CoV-2 antigens. These include S, S1, RBD, and the N protein. It was shown that among 101 these antigens tested, S1 was more specific in detecting SARS-CoV-2 antibodies while N protein 102 was more sensitive than S1. 29 While describing an ELISA method involving the full-length S 

Serological Assays for SARS-CoV-2 Infectious 189 Disease: Benefits, Limitations and Perspectives

A novel coronavirus from patients with pneumonia in 191

China novel coronavirus investigating and research team

Coronaviridae Study Group of the International Committee on Taxonomy of Viruses, the 194 species Severe acute respiratory syndrome-related coronavirus:classifying 2019-nCoV 195 and naming it SARS-CoV-2

Evolving status of the 2019 novelcoronavirus infection: proposal of 197 conventional serologic assays fordisease diagnosis and infection monitoring

The dominance of human coronavirus OC43 and 203 NL63 infections in infants

Cross-reaction of SARS-CoV antigen with autoantibodies in 205 autoimmune diseases

Antibody response of patients with severe acute 207 respiratory syndrome (SARS) targets the viral nucleocapsid

Recombinant protein-based ELISA and immuno-210 cytochemical assay forthe diagnosis of SARS

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Diagnosis of severe acute respiratory syndrome (SARS) by detection 219 of SARS coronavirus nucleocapsidantibodies in an antigen-capturing enzyme-linked 220 immunosorbent assay

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