COVID-19 testing: Which to get and when, according to a doctor

CentraCare diagnosed 3,000 positive coronavirus cases so far

ORANGE COUNTY, Fla. – Testing is a key factor in stopping the spread of COVID-19. With several options available, how do you know which test to get and when to take it?

Dr. Tim Hendrix, the medical director of AdventHealth Centra Care, said there are only two tests that diagnose coronavirus: a PCR test and the antigen test.

Hendrix said since the pandemic began, the staff at Centra Care locations across Central Florida diagnosed more than 3,000 people with coronavirus using an antigen test. These tests can provide results in minutes.

“We can do them in the office and get results in about 15 minutes,” Hendrix said. “But the caveat is there is a little bit less sensitivity in detecting the virus and a chance of false negatives.”

Hendrix said the PCR test is the “gold standard” in testing, but it takes longer to get those results back.

“With antigen testing you have convenience, you have immediate results, but a little less detection rate compared to PCR which will take at least a week to get back. We have to put those trade-offs into perspective,” he said.

Hendrix said if you are showing symptoms, get tested. But if you were exposed and not showing symptoms, then he said you should wait five days before getting tested.

"Testing right away will give you a false sense of security because it takes at least 5 days to start developing a positive test, up to 14 days," he said.

Hendrix said antibody tests currently available can cause some confusion and misunderstanding among test takers. He said an antibody test does not tell a person if they are currently infected with COVID-19.

[TIMELINE: The spread of coronavirus in Florida]

“It really has no place to the diagnosis of infection,” Hendrix said.

He said the antibody testing is only good for showing past infection because it can take up to 10 days to develop antibodies. That means you could take an antibody test and get negative results, but test positive later.

"It will give you a false sense of security because if it's negative it just means you haven't developed antibodies yet," Dr. Hendrix said.

He said antibody tests are useful for figuring out who can donate convalescent plasma which is being used to treat hospitalized COVID-19 patients.

“We can do an antibody test to determine if they’re a good candidate as a donor so they can donate their serum and those antibodies to somebody in the ICU to treat them and try to help them get through that serious infection,” Dr. Hendrix said.

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