Current and innovative methods for the diagnosis of COVID-19 infection (Review)

The Coronavirus Disease 2019 (COVID-19) pandemic has forced the scientific community to rapidly develop highly reliable diagnostic methods in order to effectively and accurately diagnose this pathology, thus limiting the spread of infection. Although the structural and molecular characteristics of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were initially unknown, various diagnostic strategies useful for making a correct diagnosis of COVID-19 have been rapidly developed by private research laboratories and biomedical companies. At present, rapid antigen or antibody tests, immunoenzymatic serological tests and molecular tests based on RT-PCR are the most widely used and validated techniques worldwide. Apart from these conventional methods, other techniques, including isothermal nucleic acid amplification techniques, clusters of regularly inter-spaced short palindromic repeats/Cas (CRISPR/Cas)-based approaches or digital PCR methods are currently used in research contexts or are awaiting approval for diagnostic use by competent authorities. In order to provide guidance for the correct use of COVID-19 diagnostic tests, the present review describes the diagnostic strategies available which may be used for the diagnosis of COVID-19 infection in both clinical and research settings. In particular, the technical and instrumental characteristics of the diagnostic methods used are described herein. In addition, updated and detailed information about the type of sample, the modality and the timing of use of specific tests are also discussed.