Florida hit a new record for coronavirus cases Friday. Officials announced more than 9,000 new confirmed cases in the state. But experts say that number is likely on the low side, in part because not all positive test results are listed in the Department of Health’s total for each day.
Florida Governor Ron DeSantis is facing criticism as health officials put out data some say contains holes, or in some cases, differs from reports put out by other groups. DeSantis showed obvious frustration over the issue during a recent press conference after a Miami Herald reporter asked him about "apparent inconsistencies."
“You guys have been on the conspiracy bandwagon for months. You have no evidence. You need to move on, you really do. It’s embarrassing at this point,” DeSantis said to the reporter.
Not All Positive Cases Get Counted
Reporters aren’t the only ones raising concerns about the data provided by the health department. Leon County Commissioner Kristen Dozier says local numbers don’t reflect people getting tested through a drive-up testing site at Patients First.
“We need to have a better understanding of what our numbers are and I think we really need to include those numbers in our daily update," Dozier said.
Patients First has been in the news in the state’s capital city lately as long lines of cars have blocked traffic and businesses along the road leading to the testing site. Patients First says it’s been testing hundreds of people a day, but positive cases from the testing site aren’t included in the health department’s numbers.
A health department official says Patients First’s numbers aren’t included because they come from a different kind of test called an antigen test. In an email, a spokesperson from the department wrote “a positive antigen test is considered a probable case. Total positive cases include results from COVID-19 PCR diagnostic tests.”
Molecular Tests, Antibody Tests And Antigen Tests, What's The Difference?
There are three main types of coronavirus tests: a PCR, or molecular test, an antigen test and an antibody test.
The PCR test, the kind the health department uses to count positive cases, and is likely what people are most familiar with. It generally involves a nasal swab and takes three to five days for results to come back. Gigi Kwik Gronvall is a senior scholar at the Johns Hopkins Center for Health Security. She says The PCR tests check for active infections.
“ So if somebody is infectious they should have virus in their blood stream or their saliva and those kinds of test should be able to pick it up so you can see that they’re actively infected,” Gronvall says.
Antigen tests also use a swab to check to for active infections. They should not be confused with antibody tests. They’re different things. An antigen test tells a person whether they’re sick right now. An antibody test tells a person if they’ve been sick at some point in the past.
Antigen tests are becoming more popular because they can give people results much more quickly—usually in about 15 minutes. Gronvall says that makes them a good option in some cases, but they also come with drawbacks.
“The rapid antigen test, those are also diagnostic. They tend to miss a lot of infection so there’s more false negatives in the rapid antigen tests, but they tend to be easier to administer at point of care,” Gronvall says.
Gronvall says the test used to check for strep is similar to the antigen test used to check for the coronavirus.
“So if you went into a medi-center and you got a rapid antigen test for strep, you know from personal experience they don’t’ catch all the infections, but they tend to be more specific. So if you get a positive result it tends to be right,” Gronvall says.
The Food and Drug Administration, says antigen tests have a higher rate of false negatives--meaning some who tests negative could still have the virus and the FDA recommends following that test up with another test. But the FDA says positive test results are highly accurate--meaning someone who tests positive very likely does have the virus. Despite that, the Florida Department of Health counts results from antigen tests as “probable cases,” and right now the number of probable cases in the state isn’t made available to the public. But that could change. In an email a spokesperson says “the Department of Health is collecting data on antigen positive cases and we are currently developing methods for public dissemination.”
