Revisão sistemática: comparação de protocolos RT-PCR no diagnóstico da Covid-19

Abstract

Discovered at the end of 2019, the COVID-19 has rapidly irradiated around the world. One of the challenges to preventing virus dispersal is the early diagnosis and isolation of infected people. In this sense, the RT-PCR technique has been the most used and is considered the “gold standard” for diagnosis, despite some limitations that can generate false-negative results. Therefore, the aim of this study was to analyze the literature reports on the most appropriate RT-PCR protocols for the COVID-19 diagnosis. We screened the PubMed database with the keywords “RT-PCR” and “SARS-CoV-2”, without language restrictions. After applying the exclusion filters, we selected 15 literature review papers that compared sample types, viral load at different stages of infection, RT-PCR quality and the best marker genes to identify the SARS-CoV-2 virus. By considering easiness sample collection and the stage of infection, nasopharyngeal and saliva samples showed high detection rates and are the matrices-of-choice for diagnosis. Alternatively, faeces and lower respiratory tract samples can also be used and are better suited for virus detection after advanced infection. Finally, gene marker detection rates were similar, but the gene N is the most indicated in most papers. However, gene N (nucleocapsid) should be used with at least one additional marker for more robust results and a lower rate of false negatives. Thus, it identifies that the RT-PCR test remains the gold standard and that it has good sensitivity for detecting SARS-CoV-2.