Diagnosing COVID-19: diagnostic importance of detecting E gene of the SARS-CoV-2 genome

Plain language summaryThis study aimed to evaluate the significance of E gene detection in addition to the detection of N and RdRp genes of SARS-CoV-2 in diagnosing COVID-19. Patients negative for the E gene were tested after symptoms disappeared and it took significantly longer to detect signals in these samples. Samples negative for the E gene were potentially false positive and clinical data should be assessed while interpreting results. Aim: To evaluate the significance of E gene analysis in addition to N and RdRp genes of SARS-CoV-2, and to compare the specificity and sensitivity of targets. Materials & methods: We used two reverse transcription-PCR assays: one targeting N, E and RdRp and the other targeting N and RdRp genes and analyzed variation in threshold cycle (Ct) values. Results: Of the 155 samples, 70.32% tested positive: all three genes were detected in 45.87%, N and RdRp in 19.27% and only N in 34.86%. Patients negative for the E gene were tested after symptoms disappeared and Ct values were significantly higher. Conclusion: Samples negative for the E gene were potentially false positive and clinical conditions should be assessed while interpreting results.