Microbiological Testing for Coronavirus Disease 2019

Abstract

Microbiological diagnosis of coronavirus disease 2019 (COVID-19) is mainly performed through nucleic acid amplification test (NAAT) and antigen test. Although NAAT is the standard diagnostic test, its use is limited by insufficient laboratory resources and long turnaround time. Point-of-care NAAT tests have been introduced to address these shortcomings, but their varied sensitivity and resource constraints remain a concern. Antigen tests require fewer resources but have low sensitivity. Nevertheless, low-sensitivity tests may be useful depending on the situation. In contrast, in some clinical phases of COVID-19, high-sensitivity tests may provide false-negative results. Therefore, the right testing strategy is needed for an accurate diagnosis. In this review, the characteristics and clinical applications of microbiological tests available in Japan (NAAT, antigen test, and antibody test) are discussed. The clinical diagnosis of COVID-19 is slightly complicated, and cases in which the infection spreads from asymptomatic infected individuals are many; hence, laboratory diagnosis is essential to prevent further transmission.

Keywords: COVID-19; Japan; antigen test; microbiological test; nucleic acid detection test.

Figure 1.

The measurement principle of real-time reverse transcription polymerase chain reaction.

Figure 2.

The serological course of coronavirus disease 2019. Reproduced from Galipeau Y, Greig M, Liu G, et al. Humoral responses and serological assays in SARS-CoV-2 infections. Front Immunol. 2020;11:610688 with permission. ^© 2020 Galipeau, Greig, Liu, Driedger and Langlois.

Figure 3.

Repeat testing strategy for the patients of coronavirus disease 2019 who need aiding in therapeutic intervention. NAAT, nucleic acid amplification tests; BALF, bronchoalveolar lavage fluid. *Consider antibody testing, if necessary.