Effect of heat inactivation on the detection of the RNA of SARS-CoV-2 by RT-qPCR

ABSTRACT

SARS-CoV-Z treated at 56 degrees C for 30 min can be inactivated effectively. However, the effect of heat treatment on subsequent detection of the RNA of SARS-CoV-2 by real-time reverse transcription-quantitative polymerase Chain reaction (RT-qPCR) has not been reported. We filled this knowledge gap in present study. We used five SARS'CoV-Z-positive throat swabs. Each throat swab was divided into four parts and assigned to a group control;56 degrees C for 30 min;56 degrees C for 45 min;56 degrees C for 60 min. After heat treatment, SARS-CoV-Z RNA was extracted and detected by RT-qPCR (absolute quantitation using a standard curve). We found that SARS- CoV-Z RNA was reduced by ~40% after treatment at 56 degrees C for 30 ' 60 min. There was no significant difference (P > 0.05 for all) in the test results between the treatment groups (56 degrees C for 30 min;56 degrees C for 45 min;56 degrees C for 60 min). Our study suggested that SARS-CoV-Z specimens could be inactivated at 56 degrees C for 30 min, before RNA extraction and RT-qPCR detection, which could protect the safety of personnel and the environment during testing. Heat inactivation had a limited effect upon RT-qPCR detection but it should be used with caution if the specimen result is near the critical value.