Thermal inactivation and nucleic acid amplification-based testing for SARS-CoV-2.

Abstract

Recently, Pang and colleagues reported that thermal inactivation of clinical samples at +56 °C adversely affected the efficiency of RT-PCR for SARS-CoV-2 detection, likely by disrupting the integrity of the SARS-CoV-2 RNA with subsequent risk of false negative results [1]. However, the impact of heat inactivation on nucleic acid amplification-based testing results remains controversial. Thus, Chen and colleagues reported that the inactivation by incubating sample at +56 °C for 30 min had no significant effect on the detection of SARS-CoV-2 by real-time RT-PCR [2]. In April 2020, Abbott Molecular (Des Plaines, IL, USA) received emergency use authorization (EUA) approval from Food and Drug Administration (FAD), USA, for real-time RT-PCR test to detect SARS-CoV-2 RNA in clinical specimens from suspected COVID-19 patients [3]. The RealTime SARS-CoV-2 assay (Abbott Molecular) amplifies target regions of the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) and nucleocapsid (N) genes. The assay is run on the automated Abbott m2000 SP/rt platform currently in use internationally by reference laboratories and university hospitals. The RealTime SARS-CoV-2 assay has been validated for clinical use, and with the high-throughput, fully automated Abbott m2000 SP/rt system, this assay will accelerate the pace of SARS-CoV-2 testing [4]. The instructions for use of the RealTime SARS-CoV-2 assay (Abbott Molecular; reference 09N77-095) do not give details on pre-analytical processing of samples, and only claims that all human sourced materials should be considered infectious and be handled using appropriate laboratory biosafety practices [3]. Iorder to provide protection of our laboratory staff, and in the absence of instruction for clinical specimen inactivation from the manufacturer, we investigated herein whether thermal inactivation could affect the results of viral detection using RealTime SARS-CoV-2 assay (Abbott Molecular).