Clinical Samples for SARS-CoV-2 Detection: Review of the Early Literature

In January 2020, a cluster of pneumonia cases was reported in Wuhan, China. A global pandemic followed. The infection, called novel coronavirus disease 2019 (COVID-19), is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Common symptoms of COVID-19 illness included fever, cough, and abnormal findings on chest computed tomography. Nucleic acid testing, in the form of real-time reverse transcriptase polymerase chain reaction, is essential for diagnosing COVID-19 from respiratory samples from infected patients. Still, many questions remain surrounding the optimization of pre-analytical factors, such as specimen selection, collection, and transport. This review summarizes the current publications that describe viral density and specimen suitability for molecular detection methods. Of note, many of the reports represent studies with small sample sizes, and information may change as more is learned about specimen types as the pandemic continues.