Analytical sensitivity comparison of 14 conventional and three rapid RT-PCR assays for SARS-CoV-2 detection

Recent reports have compared the analytical sensitivities of some SARS-CoV-2 RT-PCR assays, but differences in the viral materials used for these evaluations made comprehensive conclusions difficult. We carried out a direct comparison of the analytical sensitivities of 14 conventional and three rapid RT-PCR assays for the detection of SARS-CoV-2. The comparison was performed utilizing a certified reference material for SARS-CoV-2 RNA that was serially two-fold diluted in RNA storage solution. Our results show that the analytical sensitivities of the 17 assays varied within an 8-fold range (100-800 copies/mL). Moreover, a trend with some rapid assays yielding slightly higher analytical sensitivities (2- to 4-fold) compared with conventional assays was observed. We conclude that most of the RT-PCR assays can be used for routine COVID-19 diagnosis, but some assays with the poorest analytical sensitivities may lead to false-negative results when used to identify asymptomatic individuals who can carry a low viral load but still be infectious. These findings should be kept in mind when selecting high-sensitivity and rapid assays.