Covid-19 mass testing facilities could end the epidemic rapidlyBMJ 2020; 368 doi: https://doi.org/10.1136/bmj.m1163 (Published 22 March 2020) Cite this as: BMJ 2020;368:m1163
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I struggle to understand how testing for the presence of Covid-19 can possibly affect the course of the pandemic. The situation is compounded by the oft-quoted poor accuracy of the lateral flow test.
A test for the presence of Covid-19 carries about the same prognostic capability as that of a breathalyser test. Even if 100% accurate, which is unachievable, all one can say is that there was insufficient virus captured by the test at the time of testing, to turn it positive in the same way that the breathalyser requires a certain amount of alcohol in the breath to turn in a positive result. Just like a negative breathalyser today will not stop me from driking and driving tomorrow, and may give false reassurance on the amount I can drink before achieving illegal amounts of breath alcohol, so the negative Covid-19 test does not stop me catching the virus tomorrow or incubating the virus today to reach the threshold for positivity tomorrow.
What is alarming is that it is suggested that actions can be taken on the basis of these results, ignoring their lack of any prognostic value.
Competing interests: No competing interests