NORFOLK, Va. — Healthcare professionals are using two different types of coronavirus tests. But which one is more accurate?
There are concerns over the reliability of different coronavirus tests and questions about which one is most accurate, after Ohio governor Mike DeWine tested negative for COVID-19, hours after he tested positive.
Eastern Virginia Medical School professor and infectious disease expert, Dr. Edward Oldfield said even the very bests tests have problems with sensitivity.
“They say you can have accurate, fast, and cheap tests... but you can only have two of the three. You can’t have all three,” Oldfield said. “You can’t be accurate, fast, and cheap.”
PCR is the most accurate COVID-19 test and the one a lot of us are probably more familiar with. Your swab is sent away to a lab and results can take days to come back.
“A lot of published data suggest it has a 70 percent sensitivity. In other words, if you’re infected, 30 percent of the time it will come back negative," Oldfield said. "And that’s the best test.”
And then there are point-of-care tests or rapid tests. You get results in 15 minutes. Oldfield said these can be less reliable than PCR tests.
“Some people have suggested maybe even in the range of 10 to 20 percent less sensitive than the PCR,” he said.
Ohio Governor Mike DeWine said on Twitter he tested positive using a point-of-care test, ahead of a planned meeting with the president, and then negative using a PCR test.
“If the President is relying on these rapid point-of-care tests to clear people to be in close contact with him, without a mask, I think that’s dangerous," Oldfield said. "We just saw with DeWine... his first test could have been the negative one and he was really infected.”
But Oldfield is not discouraging people from getting tested if you have symptoms or you’ve been in contact with someone who has COVID-19.
He said whether it’s a PCR test or a point-of-care test, he stressed they are accurate for the majority of cases.
“No test is perfect," Oldfield said. “Like any test, you have to be aware of the pros and the cons. The pro is you get a result in 15 minutes, you don’t have to send it away. You’re right there. Where you’re doing the test you’re getting the answer. The negative is - you’re going to have false-negatives. You’re going to have tests come back negative when the person is actually is positive.”
Oldfield said the best way to avoid contracting COVID-19 is to continue to wear a mask when you're around others and social distance.