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Multicenter international assessment of a SARS-CoV-2 RT-LAMP test for point of care clinical application

2022; Public Library of Science; Volume: 17; Issue: 5 Linguagem: Inglês

10.1371/journal.pone.0268340

1932-6203

Suying Lü, David Duplat, Paula Benitez-Bolivar, Cielo León, Stephany D. Villota, Eliana Veloz-Villavicencio, Valentina Arévalo, Katariina Jaenes, Yuxiu Guo, Seray Cicek, Lucas Robinson, Philippos Peidis, Joel D. Pearson, James R. Woodgett, Tony Mazzulli, Patricio Ponce, Silvia Restrepo, John Morán González, Adriana Bernal, Marcela Guevara‐Suarez, Keith Pardee, Varsovia Cevallos, Camila González, Rod Bremner,

Advanced biosensing and bioanalysis techniques

Continued waves, new variants, and limited vaccine deployment mean that SARS-CoV-2 tests remain vital to constrain the coronavirus disease 2019 (COVID-19) pandemic. Affordable, point-of-care (PoC) tests allow rapid screening in non-medical settings. Reverse-transcription loop-mediated isothermal amplification (RT-LAMP) is an appealing approach. A crucial step is to optimize testing in low/medium resource settings. Here, we optimized RT-LAMP for SARS-CoV-2 and human β-actin, and tested clinical samples in multiple countries. "TTTT" linker primers did not improve performance, and while guanidine hydrochloride, betaine and/or Igepal-CA-630 enhanced detection of synthetic RNA, only the latter two improved direct assays on nasopharygeal samples. With extracted clinical RNA, a 20 min RT-LAMP assay was essentially as sensitive as RT-PCR. With raw Canadian nasopharygeal samples, sensitivity was 100% (95% CI: 67.6% - 100%) for those with RT-qPCR Ct values ≤ 25, and 80% (95% CI: 58.4% - 91.9%) for those with 25 < Ct ≤ 27.2. Highly infectious, high titer cases were also detected in Colombian and Ecuadorian labs. We further demonstrate the utility of replacing thermocyclers with a portable PoC device (FluoroPLUM). These combined PoC molecular and hardware tools may help to limit community transmission of SARS-CoV-2.