Evaluation of the Liberty16 Mobile Real Time PCR Device for Use With the SalivaDirect Assay for SARS-CoV-2 Testing.

Devyn Yolda-Carr,Noel Vega,Paul J Pickering,Darani A Thammavongsa,Anne L Wyllie,Susan J Turner

doi:10.3389/fcimb.2021.808773

Devyn Yolda-Carr, Noel Vega + Show 4 more

Open Access

https://doi.org/10.3389/fcimb.2021.808773

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Abstract

The COVID-19 pandemic has highlighted the need and benefits for all communities to be permitted timely access to on-demand screening for infectious respiratory diseases. This can be achieved with simplified testing approaches and affordable access to core resources. While RT-qPCR-based tests remain the gold standard for SARS-CoV-2 detection due to their high sensitivity, implementation of testing requires high upfront costs to obtain the necessary instrumentation. This is particularly restrictive in low-resource settings. The Ubiquitome Liberty16 system was developed as an inexpensive, portable, battery-operated single-channel RT-qPCR device with an associated iPhone app to simplify assay set-up and data reporting. When coupled with the SalivaDirect protocol for testing saliva samples for SARS-CoV-2, the Liberty16 device yielded a limit of detection (LOD) of 12 SARS-CoV-2 RNA copies/µL, comparable to the upper end of the LOD range for the standard SalivaDirect protocol when performed on larger RT-qPCR instruments. While further optimization may deliver even greater sensitivity and assay speed, findings from this study indicate that small portable devices such as the Liberty16 can deliver reliable results and provide the opportunity to further increase access to gold standard SARS-CoV-2 testing.

Highlights

Access to SARS-CoV-2 tests remains a crucial factor in effective clinical and communitywide management of COVID-19 (Larremore et al, 2021)
As the SalivaDirect protocol can still be constrained in resource-limited settings by lack of access to RT-qPCR devices, we evaluated the performance of the novel Liberty16 system for detection of SARS-CoV-2 in saliva using a singleplex version of the SalivaDirect workflow
The limit of detection (LOD) of the Liberty16 SalivaDirect Assay Is Comparable to Other PCR Instruments

Summary

Introduction

Access to SARS-CoV-2 tests remains a crucial factor in effective clinical and communitywide management of COVID-19 (Larremore et al, 2021). Despite a rapid evolution of alternative clinical diagnostic and surveillance testing approaches, their novelty has perhaps limited their widespread implementation in the field (Mardian et al, 2021). Implementation of RTqPCR testing can be impeded by the high upfront costs required to obtain the necessary instrumentation. This is restrictive in low resource settings. To provide an alternative to some of the limitations presented by traditional RT-PCR testing, the Liberty system (Ubiquitome Ltd, Auckland, New Zealand) was developed as an inexpensive, portable, battery-operated single-

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