Evaluation of filter paper to transport oro/nasopharyngeal samples to detect SARS-CoV-2 by RT-qPCR

Maiara Dos Santos Carneiro; Fabiana Caroline Zempulski Volpato; Priscila Lamb Wink; Dariane Castro Pereira; Luciana Giordani; Afonso Luís Barth

doi:10.1016/j.jviromet.2022.114587

Evaluation of filter paper to transport oro/nasopharyngeal samples to detect SARS-CoV-2 by RT-qPCR

J Virol Methods. 2022 Oct:308:114587. doi: 10.1016/j.jviromet.2022.114587. Epub 2022 Jul 20.

Authors

Maiara Dos Santos Carneiro¹, Fabiana Caroline Zempulski Volpato², Priscila Lamb Wink³, Dariane Castro Pereira⁴, Luciana Giordani⁴, Afonso Luís Barth⁵

Affiliations

¹ LABRESIS - Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
² LABRESIS - Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil; Programa de Pós-Graduação em Ciências Médicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Laboratório de Diagnóstico de SARS-CoV-2, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil.
³ LABRESIS - Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Laboratório de Diagnóstico de SARS-CoV-2, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil. Electronic address: pris_farma@yahoo.com.br.
⁴ Laboratório de Diagnóstico de SARS-CoV-2, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil.
⁵ LABRESIS - Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil; Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Programa de Pós-Graduação em Ciências Médicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Laboratório de Diagnóstico de SARS-CoV-2, Hospital de Clínicas de Porto Alegre, Rio Grande do Sul, Brazil.

Abstract

Purpose: To evaluate filter paper as a means to transport oro/nasopharyngeal samples from laboratories with few resources for SARS-CoV-2 detection by RT-qPCR in a central laboratory that usually performs this technique as routine.

Methods: A total of 40 specimens were evaluated in parallel by RT-qPCR carried out after RNA extraction using two different protocols: direct RNA extraction (Protocol A - reference method) and RNA extraction after impregnation in filter paper (Protocol B).

Results: The RT-qPCR for SARS-CoV-2 using Protocol B presented 97.22% (35/36) of agreement for SARS-CoV-2-positive samples when compared to the reference method (Protocol A), even for specimens with low viral load (increased Ct values). Noteworthy, three clinical specimens which were categorized as inconclusive by Protocol A presented amplification of both N1 and N2 targets using Protocol B, presenting positive results for SARS-CoV-2.

Conclusion: The use of filter paper to transport oro/nasopharyngeal clinical samples presented very satisfactory results to detect SARS-CoV-2 by RT-qPCR. In addition, it proved to be a feasible and sensitive approach, being able to generate the detection of SARS-CoV-2 even at low concentrations, without presenting false-negative results.

Keywords: Filter Paper; RT-qPCR; SARS-CoV-2; Transportation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19 Testing
COVID-19* / diagnosis
Clinical Laboratory Techniques / methods
Humans
RNA, Viral / analysis
RNA, Viral / genetics
SARS-CoV-2* / genetics
Sensitivity and Specificity

Substances

RNA, Viral