Diagnostics for SARS-CoV-2 detection: A comprehensive review of the FDA-EUA COVID-19 testing landscape

Abstract

The rapidly spreading outbreak of COVID-19 disease is caused by the SARS-CoV-2 virus, first reported in December 2019 in Wuhan, China. As of June 17, 2020, this virus has infected over 8.2 million people but ranges in symptom severity, making it difficult to assess its overall infection rate. There is a need for rapid and accurate diagnostics to better monitor and prevent the spread of COVID-19. In this review, we present and evaluate two main types of diagnostics with FDA-EUA status for COVID-19: nucleic acid testing for detection of SARS-CoV-2 RNA, and serological assays for detection of SARS-CoV-2 specific IgG and IgM patient antibodies, along with the necessary sample preparation for accurate diagnoses. In particular, we cover and compare tests such as the CDC 2019-nCoV RT-PCR Diagnostic Panel, Cellex's qSARS-CoV-2 IgG/IgM Rapid Test, and point-of-care tests such as Abbott's ID NOW COVID-19 Test. Antibody testing is especially important in understanding the prevalence of the virus in the community and to identify those who have gained immunity. We conclude by highlighting the future of COVID-19 diagnostics, which include the need for quantitative testing and the development of emerging biosensors as point-of-care tests.

Keywords: COVID-19; Diagnostic testing; FDA-EUA; Immunoassay; Point-of-care; RT-PCR; SARS-CoV-2.

Fig. 1

SARS-CoV-2 Virus structure, with five main proteins. Details of protein function can be found in Table 1.

Fig. 2

Time course of approximate concentrations of viral RNA, antigen, and antibodies after symptom onset for a hypothetical patient with SARS-CoV-2. Diagnostic testing consists of both RT-PCR and antigen testing. While exact numbers on the duration of the antibody response are still being determined at this writing, in general, RT-PCR and antigen testing are effective to diagnose active infection when viral RNA or antigen is present. Serological assays are effective after about 5 days to detect IgM, with IgG rising afterwards (Guo et al., 2020).