It is being warned by the scientists that coronavirus tests are not 100% reliable. What this means is that some people have coronavirus but their tests might come out negative, which is quite devastating.
It means that the governments can never be sure when to reopen their economies and give green signal back to normal life.
Most of the tests around the world are using PCR technology to detect coronavirus. It detects pieces of the coronavirus in mucus samples.
However as per an infectious diseases specialist at Mayo Clinic in Minnesota Priya Sampathkumar “there are a lot of things that impact whether or not the test actually picks up the virus.”
She said, “It depends on how much virus the person is shedding (through sneezing, coughing, and other bodily functions), how the test was collected and whether it was done appropriately by someone used to collecting these swabs, and then how long it sat in transport.”
As the virus has been spreading amongst human for just 4 months, studies regarding the reliability of the test are just starting.
The earlier reports in China suggested that its ability to return positive results when the virus is present is around 60 to 70%. But now different companies globally are having different tests so its hard to determine the precise figure.
She said, “In California, estimates say the rate of COVID-19 infection may exceed 50 percent by mid-May 2020.”
With 40 million people, “even if only one percent of the population was tested, 20,000 false-negative results would be expected.” What this means is that it is essential that clinicians base their diagnosis on patients’ symptoms as well and not just on the test.