Rapid Adaptation and Continuous Performance Evaluation of SARS-CoV-2 Envelope Gene (E-gene)


Rapid Adaptation and Continuous Performance
Evaluation of SARS-CoV-2 Envelope Gene (E-gene)
Real-Time RT-PCR Assays to Support the Hospital
Surge in Test Demand

Yolanda Iok Ieng Ho
Prince of Wales Hospital
Ann Han Wong
Department of Microbiology, Prince of Wales Hospital
Eddie Chi Man Leung
Department of Microbiology, Prince of Wales Hospital
River Chun Wai Wong
Department of Microbiology, Prince of Wales Hospital
Raymond Wai Man Lai
Department of Microbiology, Prince of Wales Hospital
Short report

Keywords: SARS-Co-V-2, E-gene, Real-time RT-PCR


DOI: https://doi.org/10.21203/rs.3.rs-38621/v1
License:   This work is licensed under a Creative Commons Attribution 4.0 International License.


Abstract

We describe timely adaption of both published WHO E-gene protocol and commercially available LightMix
Modular E-gene assay to the test platform (ABI 7900 Fast real-time analyzer and TaqMan Fast One-step
Virus Master Mix) available in an accredited tertiary hospital laboratory with on-going evaluation to ensure
provision of quality service within time constraint. The LightMix Modular E-gene was slightly more sensitive
when compared to the WHO E-gene, both analytically and diagnostically. The assay was recommended for
screening of SARS-CoV-2 infection. With the availability of technically competent staff through continuous
training, provision of round the clock service is feasible despite the test is of high complexity. The shorten
turn-around-time of about 4 hours per batch could support surges in testing demand, which is essential to
control the current SARS-CoV-2 pandemic, to prevent potential overwhelming of the healthcare system and
to optimize utilization of the isolation beds.


Background
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was rst reported in Wuhan, China, in
the end of December 2019 [1]. The genome published on January 11th 2020 (GenBank accession number
MN908947) shows a high similarity to the SARS-CoV-1 which was epidemic in Hong Kong in 2003 [2]. Early
February 2020, there were 42,708 conrmed infections and 1017 fatalities in China [3]. To control disease
spread and prevent outbreak which could overwhelm the healthcare system, rapid implementation and
provision of quality assured molecular diagnostic service is crucial.
Owing to its immediate availability, the LightMix Modular E-gene assay (Tib-Molbiol, Germany) designed for
use with the LightCycler 480 system and the LightCycler multiplex RNA virus master (both are from Roche
Diagnostics, Germany) was implemented in our laboratory for emergency use on 1st February 2020. An
alternative E-gene protocol published by Corman et al [4] is recommended by World Health Organization
(WHO) [5] and is widely used for screening of SARS-CoV-2 in Europe [6, 7]. Here we reported the timely
adaption of published protocol and commercial assay to our routine testing platform with on-going
performance evaluation to ensure provision of quality service by a National Association of Testing
Authorities (NATA, Australia) accredited laboratory.

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