Quantitative and Qualitative Determination of COVID-19 (SARS-CoV-2) Specific Antibodies Using ELISA

After the emergence of coronavirus disease-19 (COVID-19) in late 2019 spread to different countries, becoming a global health concern. It belongs to the betacoronavirus family notorious for causing two outbreaks of severe acute respiratory syndrome (SARS-CoV) and the Middle East respiratory syndrome (MERS-CoV) in the last decade, causing huge morbidities and mortalities in a large number of population. For the current pandemic of COVID-19, accurate and precise diagnosis and surveillance of the infected individuals must be tackled by providing healthcare facilities and preventive measures in hotspot regions. COVID-19 patients were observed with non-specific symptoms like dry cough, sore throat, and fever in the early phase of infection that can worsen to serve acute respiratory syndrome and shock in the later phase of infection. Besides clinical symptoms, the radiographical finding of lungs and other definitive tests like real-time-polymerase chain reaction (RT-PCR) confirms the presence of a causative agent of COVID-19. After the infection of COVID-19, the human immune system activates and tries to neutralize the infection by forming virusspecific neutralizing antibodies. These antibodies can be detected in the patient's serum and can serve as the diagnostic biomarker. Several different types of serological assays, including enzyme-linked immunosorbent assay (ELISA), immunofluorescence assay, chemiluminescence enzyme immunoassays, immunofluorescence assay, and lateral flow immune assay, used to detect the presence of antibodies in the serum of infected individuals. This chapter will focus on the quantitative and qualitative determination of SARS-CoV-2 specific antibodies by different serological assays like ELISA in COVID-19 patients.

Keywords: Antibodies, COVID-19, ELISA, Severe Acute Respiratory Syndrome-2, Serological Tests.