tetano
Editor, Senior Moderator
PLoS One
. 2022 May 11;17(5):e0268340.
doi: 10.1371/journal.pone.0268340. eCollection 2022.
Multicenter international assessment of a SARS-CoV-2 RT-LAMP test for point of care clinical application
Suying Lu[SUP] 1 2 3 [/SUP], David Duplat[SUP] 4 [/SUP], Paula Benitez-Bolivar[SUP] 4 [/SUP], Cielo León[SUP] 4 [/SUP], Stephany D Villota[SUP] 5 [/SUP], Eliana Veloz-Villavicencio[SUP] 5 [/SUP], Valentina Arévalo[SUP] 5 [/SUP], Katariina Jaenes[SUP] 6 [/SUP], Yuxiu Guo[SUP] 7 [/SUP], Seray Cicek[SUP] 7 [/SUP], Lucas Robinson[SUP] 8 [/SUP], Philippos Peidis[SUP] 1 2 3 [/SUP], Joel D Pearson[SUP] 1 2 3 [/SUP], Jim Woodgett[SUP] 1 9 [/SUP], Tony Mazzulli[SUP] 2 10 [/SUP], Patricio Ponce[SUP] 5 [/SUP], Silvia Restrepo[SUP] 11 [/SUP], John M González[SUP] 12 [/SUP], Adriana Bernal[SUP] 13 [/SUP], Marcela Guevara-Suarez[SUP] 14 [/SUP], Keith Pardee[SUP] 6 7 15 [/SUP], Varsovia E Cevallos[SUP] 5 [/SUP], Camila González[SUP] 4 [/SUP], Rod Bremner[SUP] 1 2 3 [/SUP]
Affiliations
Abstract
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.
. 2022 May 11;17(5):e0268340.
doi: 10.1371/journal.pone.0268340. eCollection 2022.
Multicenter international assessment of a SARS-CoV-2 RT-LAMP test for point of care clinical application
Suying Lu[SUP] 1 2 3 [/SUP], David Duplat[SUP] 4 [/SUP], Paula Benitez-Bolivar[SUP] 4 [/SUP], Cielo León[SUP] 4 [/SUP], Stephany D Villota[SUP] 5 [/SUP], Eliana Veloz-Villavicencio[SUP] 5 [/SUP], Valentina Arévalo[SUP] 5 [/SUP], Katariina Jaenes[SUP] 6 [/SUP], Yuxiu Guo[SUP] 7 [/SUP], Seray Cicek[SUP] 7 [/SUP], Lucas Robinson[SUP] 8 [/SUP], Philippos Peidis[SUP] 1 2 3 [/SUP], Joel D Pearson[SUP] 1 2 3 [/SUP], Jim Woodgett[SUP] 1 9 [/SUP], Tony Mazzulli[SUP] 2 10 [/SUP], Patricio Ponce[SUP] 5 [/SUP], Silvia Restrepo[SUP] 11 [/SUP], John M González[SUP] 12 [/SUP], Adriana Bernal[SUP] 13 [/SUP], Marcela Guevara-Suarez[SUP] 14 [/SUP], Keith Pardee[SUP] 6 7 15 [/SUP], Varsovia E Cevallos[SUP] 5 [/SUP], Camila González[SUP] 4 [/SUP], Rod Bremner[SUP] 1 2 3 [/SUP]
Affiliations
- PMID: 35544541
- DOI: 10.1371/journal.pone.0268340
Abstract
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.