Are two consecutive negative RT-PCRs enough to rule out COVID-19?

Link to article at PubMed

New Microbes New Infect. 2020 Aug 27:100750. doi: 10.1016/j.nmni.2020.100750. Online ahead of print.


The COVID-19 pandemic is redefining the world we live in, and scientists are struggling to find an optimal SARS-CoV-2 diagnostic tool. Routine testing is currently performed using real time reverse transcription polymerase chain reaction (RT-PCR) of upper or lower respiratory tract secretions. The objective of this article is to demonstrate the importance of conducting RT-PCRs using deep sampling when initial upper respiratory testing is negative, in cases of high index of suspicion for COVID-19. We present the case of a 47-year-old man admitted for fever and bilateral pneumonia on chest CT scan, amid the early peak of the COVID-19 pandemic, suggesting a SARS-CoV-2 infection. RT-PCR results done twice using nasopharyngeal swabs were negative. A bronchoscopy was then performed, and RT-PCR testing on bronchoalveolar lavage yielded positive results, confirming the diagnosis of COVID-19 pneumonia. In conclusion, RT-PCR samples of the lower respiratory tract likely contain a higher viral load and thus retain a higher sensitivity for SARS-CoV-2 detection.

PMID:32874594 | PMC:PMC7451052 | DOI:10.1016/j.nmni.2020.100750

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