Diagnosis of COVID-19: Facts and challenges

Zalzala, Haider Hashim

At the end of 2019, the novel coronavirus disease 2019 (COVID-19) emerged in Wuhan, China, and then spread rapidly across the country and throughout the world. The causative agent is severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2); according to the International Committee on Taxonomy of Viruses, this virus has a nucleic acid sequence that is different from other known coronaviruses but has some similarity to the beta coronavirus identified in bats. Coronaviruses are a large virus group of enveloped positive-sense single-stranded RNA. They are divided into four genera—alpha, beta, delta, and gamma—and alpha and beta coronaviruses are known to infect humans. Rapid and early diagnosis of COVID-19 is a challenging issue for physicians and other health care personnel. The sensitivity and specificity of the clinical, radiological, and laboratory tests used to diagnose COVID-19 are variable and largely differ in efficacy depending on the patient’s stage of presentation.