ABSTRACT
Background: Antibody testing are often used for serosurveillance of COVID-19. ELISA and Chemiluminesence based antibody test are quiet sensitive and specific for such serological testing. Rapid antibody tests are developed and effectively used for this purpose. But their diagnostic efficiency needs to be evaluated. So, the present study was conducted in a dedicated COVID-19 hospital in Delhi, India to evaluate the diagnostic efficacy of a Rapid antibody kit for COVID-19. Material and Method : Sixty COVID-19 confirmed cases by RT-PCR were recruited and categorized as early, intermediate and late cases based on the number of days of their first RT-PCR + ve tests, 20 subjects in each category. Twenty samples from pre-covid era were taken as controls. IgM and IgG antibodies against RBD of spike protein (S) of SARS-CoV2 virus were detected by Rapid antibody test and compared with total antibody against the nucleocapsid (N) antigen of SARS-CoV-2 by Electrochemiluminescence based Immunoassay (ECLIA). Results The detection IgM against Receptor binding domain (RBD) of spike protein by rapid kit was 0-37.5% sensitive and 0-100% specific for diagnosis of SARS-CoV-2 infection. However, efficacy of detection of IgG by rapid kit was 87–89% sensitive and 75–100% specific when compared with total antibody against N antigen measured by ECLIA based immunoassay. Conclusion It can be concluded that detection of IgM against RBD of S protein by rapid kit is not effective but IgG detection can be used as an effective diagnostic tool for SARS-COV-2 infection.
Subject(s)
COVID-19ABSTRACT
Background: Health Care Workers (HCWs) of diagnostic laboratory handling COVID positive samples are at risk and need to take protective measures. Many protective materials were not available when the pandemic reached India forcing laboratory managers to take innovative measures to protect the laboratory staffs. Methods: We made face shields from OHP sheets and substitute of biosafety cabinets from cardboard boxes fitted with hypochlorite spraying devices. Here we present if these two in-house developed safety devices when incorporated in standard operating procedure (SOP) of laboratory safety were effective in clinical biochemistry laboratory of dedicated COVID hospitals. Results: We assessed contamination of laboratory surfaces (n=6) and rate of SARS-nCov-2 positivity from their nasal and throat swab by RT-PCR among laboratory personnel (n=18) after 14 days of their use along with other routine safety devices like use of gloves, surgical masks, OT gowns etc. These HCWs were checked regularly for signs and symptoms of COVID-19 and none had any signs and symptoms during these 14days. The SARS-nCov-2 test report was negative for the staff members and no surface contamination was detected. We conclude that innovative and cost effective protective devices can be built in-house with locally available resources and are effective in preventing the spread of COVID 19 among the staff working in clinical biochemistry laboratories. Conclusions: Laboratory managers in resource scarce areas need to be innovative to face such sudden safety challenges like COVID-19 pandemic.
Subject(s)
COVID-19ABSTRACT
The ability to estimate protein-protein binding free energy in a computationally efficient via a physics-based approach is beneficial to research focused on the mechanism of viruses binding to their target proteins. Implicit solvation methodology may be particularly useful in the early stages of such research, as it can offer valuable insights into the binding process, quickly. Here we evaluate the potential of the related molecular mechanics generalized Born surface area (MMGB/SA) approach to estimate the binding free energy {Delta}Gbind between the SARS-CoV-2 spike receptor-binding domain and the human ACE2 receptor. The calculations are based on a recent flavor of the generalized Born model, GBNSR6. Two estimates of {Delta}Gbind are performed: one based on standard bondi radii, and the other based on a newly developed set of atomic radii (OPT1), optimized specifically for protein-ligand binding. We take the average of the resulting two {Delta}Gbind values as the consensus estimate. For the well-studied Ras-Raf protein-protein complex, which has similar binding free energy to that of the SARS-CoV-2/ACE2 complex, the consensus {Delta}Gbind = -11.8 {+/-} 1 kcal/mol, vs. experimental -9.7 {+/-} 0.2 kcal/mol. The consensus estimates for the SARS-CoV-2/ACE2 complex is {Delta}Gbind = -9.4 {+/-} 1.5 kcal/mol, which is in near quantitative agreement with experiment (-10.6 kcal/mol). The availability of a conceptually simple MMGB/SA-based protocol for analysis of the SARS-CoV-2 /ACE2 binding may be beneficial in light of the need to move forward fast.