Clinical validation of the isothermal RT-LAMP test for rapid diagnosis of SARS-CoV-2

Leidy Hurtado , Diana Díaz , Katherine Escorcia, Laura Flórez , Yesit Bello , Yirys Díaz , Elkin Navarro , Leonardo C. Pacheco, Nataly Galán , Ronald Maestre , Antonio Acosta, Lisandro A. Pacheco , .

DOI: https://doi.org/10.7705/biomedica.6523
Keywords: COVID-19/diagnosis, molecular diagnostic techniques, sensitivity and specificity, point-of-care testing
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Abstract

Introduction: Since the first report in Wuhan (China) in 2019, the SARS-CoV-2 virus has spread throughout the world, with a significant impact in public health. To contain its transmission, the WHO has encouraged the development of rapid, simple, sensitive and specific tests that complement qRT-PCR, as the gold standard. RT-LAMP has shown to be a good alternative to detect SARS-CoV-2 in different fluid samples.
Objective: To validate the colorimetric RT-LAMP technique using two sets of primers targeting N gene of SARS-CoV-2 in 117 nasopharyngeal swab samples previously confirmed by RT-qPCR, using the Charité/Berlin protocol.
Material and methods: A total of 153 nasopharyngeal swab samples from individuals with suspected COVID-19 were subjected to qRT-PCR and RT-LAMP using a commercial
colorimetric kit (NEB, Germany). RT-LAMP was performed using both extracted RNA samples and raw samples without prior RNA extraction, and the result was assessed by a simple color change in the reaction.
Results: Sensitivity and specificity for the previously reported RT-LAMP primers (Broughton set) targeting N gene of SARS-CoV-2 were 0.97 (0.85-1.00) and 0.81 (0.65-0.92) respectively, with CI95%. The Lalli primers targeting another region of the N gene used showed a sensitivity value of 0.96 (0.78-1.00) and a specificity of 0.77 (0.55-0.92). Without RNA extraction we found a sensitivity value of 0.95 (0.74, 1.00) and a specificity of 0.88 (0.64, 0.99). A sensitivity value of 0.95 (0.74-1.00) and a specificity 0.88 (0.64-0.99) were found without prior RNA extraction.
Conclusion: Taking together, the results showed that RT-LAMP technique could be considered as a rapid diagnostic test, easy to perform, free of sophisticated equipment, sensitive and specific to diagnose SARS-CoV-2 in nasopharyngeal swabs with and without prior RNA extraction, allowing its implementation in places with scarce resources.

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  • Leidy Hurtado División Ciencias de la Salud, Universidad del Norte, Barranquilla, Colombia https://orcid.org/0000-0001-8371-5121
  • Diana Díaz División Ciencias de la Salud, Universidad del Norte, Barranquilla, Colombia https://orcid.org/0000-0002-2228-3799
  • Katherine Escorcia Programa de Microbióloga, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0002-3135-6101
  • Laura Flórez Programa de Microbióloga, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0002-8670-8493
  • Yesit Bello Unidad de Genética y Biología Molecular, Facultad de Ciencias Básicas y Biomédicas, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0003-1006-0042
  • Yirys Díaz División Ciencias de la Salud, Universidad del Norte, Barranquilla, Colombia https://orcid.org/0000-0003-3255-6743
  • Elkin Navarro Unidad de Genética y Biología Molecular, Facultad de Ciencias Básicas y Biomédicas, Universidad Simón Bolívar, Barranquilla, Colombia; Centro de Investigaciones en Ciencias de la Vida, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0001-7567-6409
  • Leonardo C. Pacheco Unidad de Genética y Biología Molecular, Facultad de Ciencias Básicas y Biomédicas, Universidad Simón Bolívar, Barranquilla, Colombia; Centro de Investigaciones en Ciencias de la Vida, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0002-5770-3706
  • Nataly Galán Unidad de Genética y Biología Molecular, Facultad de Ciencias Básicas y Biomédicas, Universidad Simón Bolívar, Barranquilla, Colombia; Centro de Investigaciones en Ciencias de la Vida, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0002-2096-7900
  • Ronald Maestre Centro de Investigaciones en Ciencias de la Vida, Universidad Simón Bolívar, Barranquilla, Colombia; Facultad de Ciencias de la Salud, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0002-5858-9829
  • Antonio Acosta Centro de Investigaciones en Ciencias de la Vida, Universidad Simón Bolívar, Barranquilla, Colombia; Facultad de Ciencias de la Salud, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0001-7443-3982
  • Lisandro A. Pacheco Centro de Investigaciones en Ciencias de la Vida, Universidad Simón Bolívar, Barranquilla, Colombia; Facultad de Ciencias de la Salud, Universidad Simón Bolívar, Barranquilla, Colombia https://orcid.org/0000-0002-9248-4596

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How to Cite
1.
Hurtado L, Díaz D, Escorcia K, Flórez L, Bello Y, Díaz Y, et al. Clinical validation of the isothermal RT-LAMP test for rapid diagnosis of SARS-CoV-2. Biomed. [Internet]. 2022 Oct. 31 [cited 2025 Apr. 4];42(Sp. 2):59-72. Available from: https://revistabiomedicaorg.biteca.online/index.php/biomedica/article/view/6523

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Published
2022-10-31
Issue
Vol. 42 No. Sp. 2 (2022): Covid-19
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Original articles

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