Chapter 4 - COVID-19 diagnosis: approaches and challenges

Abstract

The rapid spread of COVID-19 across the globe led to the declaration of a “Public Health Emergency” by the World Health Organization (WHO) in early 2020. In view of the large number of asymptomatic and mildly symptomatic transmitters of the virus and the overlapping nature of clinical manifestations, WHO advocated the strategy of “testing, tracing and isolation” (TTI) for the containment of the pandemic. This need for large-scale testing has led to the inception of a number of modalities based on detection of the viral RNA or antigens from a range of clinical samples. The diagnostic tools available today encompass a variety of molecular platforms including the gold standard method of RT-PCR, isothermal assays, CRISPR-based techniques, cartridge-based NAATs; are characterized by widely variable technical complexities and turn-around times; and employ a wide range of respiratory samples and saliva. Moreover, triggered by the need for simple and cheap point-of-care tests, antigen testing has also been used widely in COVID-19 diagnostics. Despite the plethora of diagnostic solutions available, the need for a rapid, accurate, simple and inexpensive test still remains unfulfilled. In this chapter, we aim at presenting an update on the existing and upcoming diagnostic procedures for COVID-19.