The primary type of testing for the novel 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. The rate of false-negatives then increases every day afterward.
On day five of infection, which is when symptoms of COVID-19 typically begin to appear, and when people are often encouraged to seek out testing, the study found the false-negative rate is 38 per cent.
Story continues below advertisement
“The probability of a false-negative result declines throughout the course of infection,” said Dr. Lauren Kucirka, a resident physician at Johns Hopkins and co-author of the study.
“If you test someone immediately after they’re infected,
Support Local Journalism
By supporting us directly, you are ensuring that local journalism stays alive and remains independent.
When you become a Monthly or Yearly Supporter, you get a free mug. Plus, for the month of August, you will also receive a $10 gift card to Tim Hortons as an extra bonus!
Thanks for reading and thanks for supporting Energeticcity.ca!