Promlek T, Thanunchai M, Phumisantiphong U, Hansirisathit T, Phuttanu C, Dongphooyao S, Thongsopa W, Nuchnoi P. Performance of colorimetric RT-LAMP as a diagnostic tool for SARS-CoV-2 infection during the fourth wave of COVID-19 in Thailand.
Int J Infect Dis 2021;
116:133-137. [PMID:
34958929 PMCID:
PMC8709723 DOI:
10.1016/j.ijid.2021.12.351]
[Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/20/2021] [Accepted: 12/20/2021] [Indexed: 11/27/2022] Open
Abstract
Background
COVID-19, which is caused by SARS-CoV-2 and its variants, poses an ongoing global threat, particularly in low-immunization coverage regions. Thus, rapid, accurate, and easy-to-perform diagnostic methods are in urgent demand to halt the spread of the virus.
Objectives
We aimed to validate the clinical performance of the FastProof 30 min-TTR SARS-CoV-2 reverse transcription loop-mediated isothermal amplification (RT-LAMP) method using leftover RNA samples extracted from 315 nasopharyngeal swabs. The sensitivity and specificity of RT-LAMP were determined in comparison with reverse transcriptase–polymerase chain reaction (RT-PCR).
Results
Of 315 nasopharyngeal swabs, viral RNA was detected in 154 samples (48.9%) by RT-PCR assay. Compared with RT-PCR, overall sensitivity and specificity of RT-LAMP were 81.82% (95% CI: 74.81–87.57) and 100% (95% CI: 97.73–100), respectively. A 100% positivity rate was achieved in samples with cycle threshold (Ct) <31 for RT-PCR targeting the ORF1ab gene. However, samples with Ct >31 accounted for false-negative results by RT-LAMP in 28 samples.
Conclusions
RT-LAMP reliably detected viral RNA with high sensitivity and specificity and has potential application for mass screening of patients with acute COVID-19 infection when viral load is high.
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