coronavirus around the world, including Canada, produces “false-negative” results at least 20 per cent of the time, researchers from Johns Hopkins University found.According to a study published in the Annals of Internal Medicine in May, the false-negative rate of RT-PCR testing used to detect the novel coronavirus changes depending on where a person is in the timeline of the infection cycle.
On day 1 of an infection, the test is completely ineffective at detecting the virus, while on day 8 of infection the test produces false negatives 20 per cent of the time, the study found.