Review of the Microbiological Diagnostic Approaches of COVID-19

On March 12, the World Health Organization declared a pandemic following the exponential increase of SARS-CoV-2 cases. The rapid spread of the virus is due to both its high infectivity and the free circulation of unrecognized infectious cases. Thus, diagnostic testing is a key element to prevent further dissemination of the virus. Urged by WHO's call, laboratories worldwide have been working on nucleic acid tests protocols and immunoassays that became available, albeit poorly validated, within a comparatively short time. Since then, external studies evaluating these diagnostic tests have been published. The present study is a review of the COVID-19 diagnostic approaches, discussing both direct and indirect microbiological diagnoses. A compendium of the literature on commercial assays kits available to date is provided together with the conclusions drawn as well as RT-PCR protocols published by the WHO. Briefly, diagnostic accuracy varies according to time elapsed since symptom onset and evolves together with understanding of the COVID-19 disease. Taking into account all these variables will allow determining the most adequate diagnostic test to use and how to optimize diagnostic testing for COVID-19.