Pathologist answers questions about COVID-19 testing
LAKE CHARLES, La. (KPLC) -Here at the pathology lab in Lake Charles, they not only swab patients to test for COVID but they do the analytical work too-- so it does not have to be sent off.
Pathologist Dr. John VanHoose says a lot of people want a test but are not sure what kind. He explains the gold standard is the PCR test which is the most reliable.
“When you first get exposed to the virus none of the tests are going to be positive. The PCR test will actually show up positive first. They can show up as soon as two days after you’ve been exposed, and they’re going to peak at about four or five days,” said VanHoose.
He says they do not do what are called antigen tests because he says they are not as reliable or useful.
“While it is rapid and that part is good, the part that is not good is that they have false positives and false negatives and false positives. And so, a lot of people think when they get testing done, that those results are one hundred per cent accurate. In fact, no test is 100% accurate. They all have false negatives and false positives.”
He does not think the test for antibodies is so useful either, since it doesn’t indicate whether a person is contagious and there’s no guarantee how long antibodies protect.
And if you are going to get a PCR test-- he says timing is important.
“If you’re not showing any symptoms it’s likely a test isn’t going to help you at all,” he said.
VanHoose says it’s kind of like a pregnancy test in that, it might show a false negative first time.
“That’s actually a great analogy because a positive means you’re pregnant. A negative does not necessarily mean that you’re not pregnant,” he said.
“You can’t really tell a person is negative from the testing because they may just being tested too soon .and until they build up enough of the virus in their body to turn the test positive, and so the test is going to continue to be negative and so that would be called, in a person who has the virus, a false negative,” he said.
Plus, VanHoose says a positive test, after being sick, does not necessarily mean you’re still contagious. Though he says an antibody test may indicate whether a person could provide convalescent plasma.
The CDC has a tremendous amount of guidance on different types of testing, who should get tested, who should quarantine, how to protect yourself and stop the spread. more.
The Pathology Lab has a capacity to do 600 COVID tests a day with a 24-48 hour turnaround, according to VanHoose.
VanHoose points out, if a test is ordered by your doctor, it’s more likely to be covered by insurance.
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