can this happen? And the next question is how can this happen? Researchers say it boils down to what kind of test you use and how they are used.
Types of COVID Tests
The many types of tests available are sowing considerable confusion. Unfortunately, because this novel coronavirus is new, and COVID-19 is a new disease, information about these tests is incomplete and the options for testing keep changing.
But according to Harvard Health, here’s what we know now about tests designed to diagnose a current infection and those that show whether you previously had the virus.
Diagnostic tests for current infection
If you want to know if you are currently infected with the COVID-19 virus, there are two types of tests: molecular tests and antigen testing.
Molecular tests (also called PCR tests, viral RNA tests, nucleic acid tests)
How is it done? Nasal swabs, throat swabs, and tests of saliva or other bodily fluids.
Where can you get this test? At a hospital, in a medical office, in your car, or even at home.
What does the test look for? Molecular tests look for genetic material that comes only from the virus.
How long does it take to get results? It depends on lab capacity. Results may be ready the same day, but usually take at least a day or two.
Throughout the pandemic, especially lately, delayed turnaround times of up to a week or two have been reported in many places.
What about accuracy? False negatives — that is, a test that says you don’t have the virus when you actually do have the virus — may occur. The reported rate of false-negatives is as low as 2% and as high as 37%. The false-positive rate — that is, how often the test says