Comparative analysis of specificity and sensitivity between Cobas 6800 system and SARS-CoV-2 rRT-PCR to detect COVID-19 infection in clinical samples

Fast and reliable testing for the COVID 19 infection is the need of the hour for the development of effective and reliable tools and assays. However, it is difficult to find the performance relativity among all these tests which are poorly understood. In this study, we aimed to evaluate the two different platforms where we determine the difference of sensitivity and specificity between the fully automated analyzer (Roche Diagnostics Cobas 6800 SARS-CoV-2 test) under FDA Emergency Use Authorization (EUA) and the laboratory designed test (SARS-CoV-2 rRT-PCR) based on the protocol developed by ICMR (Indian Council for Medical Research). The study was conducted for individual samples. We performed our study with two different approaches, first with validation method consisting of 188 samples (2 batches) on cobas 6800 instrument (Roche Molecular Systems, Branchburg, NJ) soon after we received US FDA EUA on 1 June 2021, all these samples were tested earlier with laboratory designed tests on 25th and 26th May 2021. Over all agreement between the two tests is of 88% and the coefficient of agreement between the two testing platform Cohen's kappa coefficient was found to be 0.76 (95% CI, 2.5897-13.4103) suggesting the substantial agreement between the two platforms. However, in some of the cases, both tests have shown a little disagreement. An overall discordance rate between two systems was found 11.1%. The difference may be due to the limit of detection, variation in the sequences of the primer design or may be due to other factors depicting the importance of comparing the two platforms used in the testing for SARS-CoV-2. Second approach includes head to head evaluation which comprises 1631 samples showed overall agreement of 99% and kappa value of 0.98. These results showed that cobas is effective and reliable assay for the detection of SARS-CoV-2 infection.