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. 2023 Jun 8;20(1):119.
doi: 10.1186/s12985-023-02032-z.

Assessing the comparability of cycle threshold values derived from five external quality assessment rounds for omicron nucleic acid testing

Gaowei Fan #  1   2 , Yali Jin #  3 , Qingtao Wang  4   5   6 , Yuhong Yue  7   8   9
Affiliations

Assessing the comparability of cycle threshold values derived from five external quality assessment rounds for omicron nucleic acid testing

Gaowei Fan et al. Virol J. .

Abstract

Background: A variety of open-system real-time reverse transcriptase polymerase chain reaction (RT-PCR) assays for several acute respiratory syndrome coronavirus 2 are currently in use. This study aimed to ensure the quality of omicron nucleic acid testing and to assess the comparability of cycle threshold (Ct) values derived from RT-PCR.

Methods: Five external quality assessment (EQA) rounds using the omicron virus-like particles were organized between February 2022 and June 2022.

Results: A total of 1401 qualitative EQA reports have been collected. The overall positive percentage agreement was 99.72%, the negative percentage agreement was 99.75%, and the percent agreement was 99.73%. This study observed a significant variance in Ct values derived from different test systems. There was a wide heterogeneity in PCR efficiency among different RT-PCR kits and inter-laboratories.

Conclusion: There was strong concordance among laboratories performing qualitative omicron nucleic acid testing. Ct values from qualitative RT-PCR tests should not be used for clinical or epidemiological decision-making to avoid the potential for misinterpretation of the results.

Keywords: Comparability; Cycle threshold; Omicron; Qualitative test; RT-PCR; SARS-CoV-2.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Fig. 1
Fig. 1
The Ct values derived from EQA samples were detected by different RT-PCR kits. a The Ct values determined by different RT-PCR kits combined with different extraction kits and different PCR instruments, b the Ct values determined by different RT-PCR kits combined with the Tianlong nucleic extraction kit and different PCR instruments, c the Ct values determined by different RT-PCR kits combined with the DaAn nucleic extraction kit and different PCR instruments, d the Ct values determined by different RT-PCR kits combined with Tianlong nucleic extraction kit and ABI7500 PCR instrument
Fig. 2
Fig. 2
The Ct values derived from EQA samples were detected by different extraction kits. a The Ct values determined by different extraction kits combined with BioGerm RT-PCR kit and different PCR instruments, b the Ct values determined by different extraction kits combined with BioGerm RT-PCR kit and ABI7500 PCR instrument, c the Ct values determined by different extraction kits combined with BioGerm RT-PCR kit and SLAN PCR instrument
Fig. 3
Fig. 3
The Ct values derived from EQA samples were detected by different PCR instruments. a The Ct values determined by Tianlong nucleic extraction kit and BioGerm RT-PCR kit combined with different PCR instruments, b the Ct values determined by Zybio nucleic acid extraction kit and BioGerm RT-PCR kit combined with different PCR instruments
Fig. 4
Fig. 4
The Ct values derived from EQA samples were detected by different laboratories using the same test system
See this image and copyright information in PMC

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References

    1. Karim SSA, Karim QA. Omicron SARS-CoV-2 variant: a new chapter in the COVID-19 pandemic. The Lancet. 2021;398:2126–2128. doi: 10.1016/S0140-6736(21)02758-6. - DOI - PMC - PubMed
    1. Cassone A, Crisanti A. Can reasoned mass testing impact covid-19 outcomes in wide community contexts? An evidence-based opinion. Pathog Glob Health. 2021;115:203–207. doi: 10.1080/20477724.2021.1878444. - DOI - PMC - PubMed
    1. Aranha C, Patel V, Bhor V, Gogoi D. Cycle threshold values in RT-PCR to determine dynamics of SARS-CoV-2 viral load: an approach to reduce the isolation period for COVID-19 patients. J Med Virol. 2021;93:6794–6797. doi: 10.1002/jmv.27206. - DOI - PMC - PubMed
    1. Han X, Li J, Chen Y, Li Y, Xu Y, Ying B, et al. SARS-CoV-2 nucleic acid testing is China’s key pillar of COVID-19 containment. The Lancet. 2022;399:1690–1691. doi: 10.1016/S0140-6736(22)00577-3. - DOI - PMC - PubMed
    1. Dong G-P, Guo X-J, Sun Y-A, Zhang Z, Du L-P, Li M-Y. Diagnostic techniques for COVID-19: a mini-review of early diagnostic methods. J Anal Test. 2021;5:314–326. doi: 10.1007/s41664-021-00198-5. - DOI - PMC - PubMed