LAUSR

Background:Coronavirus disease 2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS CoV-2) was declared as a pandemic on March 11, 2020 by WHO. Laboratory diagnosis is essential not only for diagnosis and management but is also required for containment and mitigation strategies to prevent the transmission. Multiple ICMR- approved RT-PCR kits are currently available which are being used for diagnosis of COVID-19. This study was carried out with the aim to compare the Sensitivity, Specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV) and agreement of the eight different RT-PCR kits for the diagnosis of COVID-19 Methods:The study was performed in Department of Microbiology, ABVIMS & Dr RMLH, and New Delhi. A total of 45 nasopharyngeal and/or oropharyngeal swabs in VTM from suspected COVID-19 patients were received in the laboratory for RT-PCR. These samples were tested by 8 different ICMR approved RT-PCR kits with different gene targets. The com- parison was made with NIV, Pune COVID-19 RT-PCR kit. Sensitivity, Specificity, PPV and NPV were calculated for each kit. Agreement of different kits was evaluated using Kappa analysis. Results:The results of the 45 samples of suspected COVID-19 cases were recorded as per the cycle threshold (Ct) provid- ed in the kit insert. Of these, 15 samples detected both E and RdRp genes and 30 were negative for both the genes of SARS CoV-2 by NIV, Pune COVID-19 RT-PCR kit. 15 samples which were positive by NIV, Pune kit were positive by all oth- er kits. Three kits showed 100% agreement with NIV, Pune COVID-19 RT-PCR kit and 4 kits had agreement of 91%, 81% 75% and 66% respectively. Conclusions:The reporting should be carried as per manufacturer’s instruction. However, samples having Ct values ≥ 35 showed variable results with different RT- PCR kits;hence the results should be interpreted with caution.