Comparison of Fourteen Rapid Point-of-Care Antigen Tests for SARS-CoV-2: Use and Sensitivity

Round 1

Reviewer 1 Report

The authors present a comparison of numerous rapid antigen-detection tests for SARS-CoV-2 benchmarked against real-time PCR. While of potential value, the basic comparison of sensitivity between tests is fundamentally flawed because the samples against which each were evaluated are not the same and the composition of the testing samples is different - most noteworthy is the Discussion comment "a large range of sensitivity was found, from 42.10% using the tests by the nal von minden and Tody Laboratories to 84.78% with the COVID-19 Ag Gold Saliva from PCL" - this is implicitly unfair as the former was tested against samples skewed to low burdens (5 with Ct < 22, 6 with Ct 23-29 and 8 > 30) whereas the latter was more balanced (11 with Ct < 22, 24 with Ct 23-29 and 11 > 30). The authors should balance the samples being compared in a better fashion. 

It is also necessary to expand the number of samples evaluated for many tests (i.e. Fujirebo, where 44% sensitivity was reported based upon a very small and very skewed test panel: 2 with Ct < 22, 2 with Ct 23-29 and 5 with Ct > 30)

Author Response

Authors would like to acknowledge the reviewer comments. If it is true that there is a bias on the expression of the sensitivity results obtained for the different RAgDT due to the different number of samples tested for each one, this was due to the need of rationalised our material in the best way possible, as in our laboratory, we had access to a limit number of each RAgDT on different moments. This clarification will be added to the manuscript and address as a limitation of the study, regretting that without the possibility of increasing the number of samples tested for the mentioned tests.

Reviewer 2 Report

This paper indicates the comparison of 14 rapid POCT antigen tests for SARS-CoV-2. I think that this study is important, both clinically and epidemiologically. The results are well organized and the conclusions are clearly stated. I recommend that this article is accepted in present form.

SARS-COV-2 antigen tests are simple and easy to use in clinics. However, it is well known that there is a problem in terms of sensitivity. This paper compares 14 kinds of antigen test kits and the results of the RT-PCR, and summarizes the sensitivity of antigen tests in an easy-to-understand manner. Although the novelty is not so high, I recommend to accept this paper because it is an important knowledge for many researchers in this research field. It will be better if they give more detailed RT-PCR experiments.

Author Response

The authors appreciate the comments of Reviewer 2 to our work. Mention has been added to the bibliography in which our in-house RT-qPCR is used in the Material and Methods section.

Round 2

Reviewer 1 Report

While acknowledging the deficiencies of the submission the authors have not addressed them. While this may be scientifically difficult, a fair and balanced assessment is critical for the stated goal of the study

Author Response

We sincerely regret to reply that it is impossible for us to increase the number of samples as requested by the reviewer. We fully understand the reviewer comments, and although we have tried to get more RAgDT we have not been able to do so.

As we did in the previous review, we recognize that the limitation in the number of samples tested is a bias for our study. However, we also believe it is important to present the data, although scarce, to give a slight idea of the expected sensitivity of these RAgDT.