Laboratory Diagnosis of SARS-CoV-2 Infections: Current Status

The ongoing unprecedented outbreak of pneumonia caused by a novel coronavirus (SARS-CoV-2) in Wuhan, China has highlighted the necessity for readily available, accurate and rapid diagnostic testing methods. The laboratory diagnostic methods for human coronavirus infections have evolved substantially, with the development of novel assays as well as the availability of updated tests for emerging ones. Newer laboratory methods are rapid, highly sensitive and specific, and are gradually replacing the conventional gold standards. This presentation reviews the current laboratory methods available for testing coronaviruses by focusing on the SARS-CoV-2 outbreak going on in Wuhan. Viral pneumonias typically do not result in the production of purulent sputum. Thus, a nasopharyngeal swab is usually the collection method used to obtain a specimen for testing. Nasopharyngeal specimens may miss early infection; a deeper specimen may need to be obtained by bronchoscopy. While real-time PCR run on separately extracted nucleic acids has been urgently used with uncertain accuracy, serology may facilitate etiology diagnosis and ultimately play a major role in determining the epidemiology of this outbreak. Alternatively, repeated testing can be used because over time, the likelihood of the SARS-CoV-2 being present in the nasal-pharynx increases. Several integrated, random-access, point-of-care molecular devices are developing for rapid and accurate diagnosis of SARS-CoV-2 infections. These assays are simple, rapid and safe and can be used in the local hospitals and clinics bearing the burden of identifying and treating patients.