Brief comparative evaluation of six open one-step RT-qPCR mastermixes for the detection of SARS-CoV-2 RNA using a Taqman probe.

BACKGROUND

Facing the emergence of a new RNA virus, clinical laboratories are often helpless in the case of a shortage of reagents recommended by Reference Centres.

OBJECTIVES

To compare five open one step RT-qPCR reagents to the SuperScript™ III Platinum™ One-Step qRT-PCR kit (Invitrogen) considered as the reference one in France at the beginning of the pandemic for detection of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in respiratory specimens by using a laboratory-developed assay targeting the viral RNA dependant RNA polymerase (RdRp) gene.

STUDY DESIGN

A total of 51 NUCLISENS easyMAG extracts from respiratory specimens was tested on ABI 7500 thermocycler with TaqMan Fast Virus 1-Step Master Mix (Applied Biosystems), Luna® Universal Probe One-Step RT-qPCR Kit (New England Biolabs), GoTaq® Probe 1- Step RT-qPCR System (Promega), LightCycler® Multiplex RNA Virus Master (Roche) and One-step PrimeScript RT-PCR kit (Takara). The CT values obtained using the 5 challenged reagents were compared to those obtained using the reference assay.

RESULTS

The percentages of concordance were all above 95 %. When comparing the CT values of the 48 extracts exhibiting CT values < 35 obtained with the reference reagent, the results were similar between the reagents although the differences of CT values were quite dispersed.

CONCLUSIONS

All five reagents can be considered as alternative reagents to the reference for detecting SARS-CoV-2 RNA.