tetano
Editor, Senior Moderator
J Med Virol
. 2022 Sep 21.
doi: 10.1002/jmv.28165. Online ahead of print.
Positive SARS-CoV-2 RT-qPCR of a nasal swab spot after 30 days of conservation on filter paper at room temperature
Guillaume André Durand[SUP] 1 2 [/SUP], Abdennour Amroun[SUP] 2 [/SUP], Gilda Grard[SUP] 1 2 [/SUP], Cyril Badaut[SUP] 1 2 [/SUP]
Affiliations
Abstract
We tested the use of nasal swabs spotted onto filter paper (Whatman 3M, Germany) for the molecular diagnosis of SARS-CoV-2 infection. Spots of a positive nasal swab in conservation medium (B.1.177 strain, 21Ct) were still positive (duo E-gene/IP4) after 10, 20, and 30 days of conservation at room temperature, with Ct values of 28, 27, and 26, respectively. Direct spotting of the swab at bedside (omicron strain) still gave a positive result after 10 days in two RT-qPCR systems: 33.7 Ct using duo E-gene/IP4, and 34.8 using a specific Omicron system. Spotting of a dilution range of media spiked with the Delta (strain 2021/FR/0610, lineage B 1.617.2) and Omicron strains (strain UVE/SARS-CoV-2/2021/FR/1514) showed a threshold of 0.04 TCID50 after 10 days of conservation. We show, for the first time, that this simple and low-cost conservation method can be used to store samples for RT-qPCR against SARS-CoV-2 for up to at least one month. This article is protected by copyright. All rights reserved.
Keywords: Cellular Effect; Disease control; RNA extraction; RNA stability; Research and Analysis Methods; SARS coronavirus; Virus classification.
. 2022 Sep 21.
doi: 10.1002/jmv.28165. Online ahead of print.
Positive SARS-CoV-2 RT-qPCR of a nasal swab spot after 30 days of conservation on filter paper at room temperature
Guillaume André Durand[SUP] 1 2 [/SUP], Abdennour Amroun[SUP] 2 [/SUP], Gilda Grard[SUP] 1 2 [/SUP], Cyril Badaut[SUP] 1 2 [/SUP]
Affiliations
- PMID: 36131355
- DOI: 10.1002/jmv.28165
Abstract
We tested the use of nasal swabs spotted onto filter paper (Whatman 3M, Germany) for the molecular diagnosis of SARS-CoV-2 infection. Spots of a positive nasal swab in conservation medium (B.1.177 strain, 21Ct) were still positive (duo E-gene/IP4) after 10, 20, and 30 days of conservation at room temperature, with Ct values of 28, 27, and 26, respectively. Direct spotting of the swab at bedside (omicron strain) still gave a positive result after 10 days in two RT-qPCR systems: 33.7 Ct using duo E-gene/IP4, and 34.8 using a specific Omicron system. Spotting of a dilution range of media spiked with the Delta (strain 2021/FR/0610, lineage B 1.617.2) and Omicron strains (strain UVE/SARS-CoV-2/2021/FR/1514) showed a threshold of 0.04 TCID50 after 10 days of conservation. We show, for the first time, that this simple and low-cost conservation method can be used to store samples for RT-qPCR against SARS-CoV-2 for up to at least one month. This article is protected by copyright. All rights reserved.
Keywords: Cellular Effect; Disease control; RNA extraction; RNA stability; Research and Analysis Methods; SARS coronavirus; Virus classification.