Detection of SARS-CoV-2 using real-time polymerase chain reaction in different clinical specimens: A critical review

Abstract

Coronavirus disease 2019 (COVID-19) is a disease caused by a new strain of coronavirus namedas severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Globally, since the outbreak,more than seven million confirmed cases of COVID-19 have been reported. The rapid spreadand increase in the number of new cases is due to person-to-person transmission. To furthercontrol its transmission, early laboratory diagnosis of both asymptomatic and symptomaticpatients is crucial. Presently, the COVID-19 diagnosis of infected individuals is dependent oncomputed tomography scanning and real-time polymerase chain reaction (PCR). The latter isconsidered more sensitive and efficient for early diagnosis. In this review, general comparisonsare made (cases, fatality rate, incubation period, clinical features, and reservoirs) and diagnosticlaboratory procedures (specimens, extraction methods, and positive rates by real-timePCR) are compared between SARS, Middle East Respiratory Syndrome, and SARS-2. In total,8982 SARS-2 suspected patients specimen data were retrieved, in which 40.9% (n = 3678) weredetected as positive by real-time PCR. The specimen-wise high detection rate was observedfrom bronchoalveolar lavage, followed by saliva, nasal swabs, and sputum. As the COVID-19cases are persistently increasing, the selection of appropriate specimens and laboratory assaywould help in rapid and timely diagnosis