An alternative colorimetric RT-LAMP assay for the rapid detection of SARS-CoV-2: development and validation in Thailand

Wiphat Klayut; Thanee Wongchai; Nattagarn Chuenchom; Payu Bhakdeenuan; Supranee Bunchoo; Sopa Srisungngam; Sirilada Suphankong; Benjawan Phetsuksiri; Ballang Uppapong; Janisara Rudeeaneksin

doi:10.3855/jidc.19442

An alternative colorimetric RT-LAMP assay for the rapid detection of SARS-CoV-2: development and validation in Thailand

Authors

Wiphat Klayut National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0000-0002-4396-0410
Thanee Wongchai Mae Sot Hospital, Ministry of Public Health, Tak, Thailand https://orcid.org/0009-0009-0765-7295
Nattagarn Chuenchom Mae Sot Hospital, Ministry of Public Health, Tak, Thailand https://orcid.org/0009-0001-0267-7993
Payu Bhakdeenuan National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0009-0005-5486-3631
Supranee Bunchoo National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0009-0003-1454-5116
Sopa Srisungngam National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0009-0007-8589-2309
Sirilada Suphankong Regional Medical Sciences Center 5 Samut Songkhram, Department of Medical Sciences, Ministry of Public Health, Samut Songkhram, Thailand https://orcid.org/0009-0008-5263-2743
Benjawan Phetsuksiri Medical Sciences Technical Office, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0000-0001-6507-2898
Ballang Uppapong National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0009-0004-1879-0618
Janisara Rudeeaneksin National Institute of Health, Department of Medical Sciences, Ministry of Public Health, Nonthaburi, Thailand https://orcid.org/0009-0001-4859-7243

DOI:

https://doi.org/10.3855/jidc.19442

Keywords:

COVID-19, SARS-CoV-2, RT LAMP, rtRT-PCR, colorimetric

Abstract

Introduction: COVID-19, an emerging infectious disease caused by SARS-CoV-2, continues to be a global public health threat. The development of a colorimetric reverse transcription loop-mediated isothermal amplification (RT-LAMP) can extend the availability of simple, reliable molecular tests for the rapid detection of COVID-19.

Methodology: The RT-LAMP assay was developed using a new primer set targeting a portion of SARS-CoV-2 orf8. The method was validated at 63 ºC for 60 minutes with naked-eye visualization of the color change. The clinical performance was compared to a real-time reverse transcription-polymerase chain reaction (rtRT-PCR) using 273 RNA samples extracted from nasopharyngeal swab specimens.

Results: The developed RT-LAMP was specific to SARS-CoV-2 with a limit of detection at 15 RNA copies per reaction. The assay demonstrated diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 90.48% (95% CI: 86.36–93.68%), 87.00% (95% CI: 81.53–91.33%), 100% (95% CI: 95.07–100%), 100% (95% CI: not available), and 73.74% (95% CI: 66.22–80.07%), respectively, compared to the rtRT-PCR. The greatest sensitivity of 98.03% (95% CI: 94.34–99.59%) was demonstrated in samples with the cycle threshold (Ct) values < 30 cycles.

Conclusions: The RT-LAMP method in this study showed good performance. The assay can increase the scope of laboratory testing for rapidly detecting SARS-CoV-2 in Thailand. Due to a decrease in COVID-19 cases, its application is beneficial when commercial alternatives are unavailable.

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Published

2024-08-31

How to Cite

Klayut W, Wongchai T, Chuenchom N, Bhakdeenuan P, Bunchoo S, Srisungngam S, Suphankong S, Phetsuksiri B, Uppapong B, Rudeeaneksin J (2024) An alternative colorimetric RT-LAMP assay for the rapid detection of SARS-CoV-2: development and validation in Thailand. J Infect Dev Ctries 18:1196–1203. doi: 10.3855/jidc.19442

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Issue

Vol. 18 No. 08: August 2024

Section

Coronavirus Pandemic

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Copyright (c) 2024 Wiphat Klayut, Thanee Wongchai, Nattagarn Chuenchom, Payu Bhakdeenuan, Supranee Bunchoo, Sopa Srisungngam, Sirilada Suphankong, Benjawan Phetsuksiri, Ballang Uppapong, Janisara Rudeeaneksin

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