Centers for Disease Control and Prevention (CDC) acknowledged that it’s combining the results from viral and antibody COVID-19 tests when reporting the country’s testing totals, despite marked differences between the tests.
First reported by NPR’s WLRN station in Miaimi, the practice has drawn ire from U.S. health experts who say combining the tests inhibits the agency’s ability to discern the country’s actual testing capacity.
“You’ve need to be kidding me,” Ashish Jha, director of the Harvard Global Health Institute, told The Atlantic. “How could the CDC make that mistake? this is often a multitude .”
Viral tests – commonly mentioned as PCR tests as most of them use a process referred to as polymerase chain reaction – are employed by health professionals to work out whether or not an individual is currently infected with the disease. During the pandemic, viral tests are the foremost effective way of having the ability to diagnose a positive case of COVID-19. they’re what state governments are counting to trace the amount of confirmed cases of the virus they need .
Antibody, or serology, tests serve a special purpose. Unlike viral tests that are taken by nose swab or saliva sample, antibody tests examine an individual’s blood to ascertain if their system has created antibodies to combat COVID-19. These tests allow doctors to ascertain if someone has previously been exposed to the virus. because the push for widespread testing within the U.S. has strengthened, antibody tests are widely produced, many experts have balked at saying that antibodies equate to immunity from COVID-19. Serology tests also are less accurate than PCR tests, increasing the probabilities for a false negative.
Moreover, a negative test means various things for either test. A negative PCR test indicates to physicians that the patient isn’t currently ill with the disease. But, a negative serology test means the patient has presumably not been exposed to or infected with COVID-19.
“The viral testing is to know what percentage people are becoming infected, while antibody testing is like looking within the car mirror . the 2 tests are totally different signals,” Jha told The Atlantic.
In a statement, CDC spokesperson Kristen Nordlund told Capitol Hill that when the agency began to trace coronavirus testing, viral tests were much more commonly used nationwide than serology testing.”
“Now that serology testing is more widely available, CDC is functioning to differentiate those tests from the viral tests and can report this information, differentiated by test type, publicly on our COVID Data Tracker website within the coming weeks,” she said.
According to reports, several states, including Pennsylvania, Georgia, Texas and Florida, have also been combining the results of the 2 tests.
The combining of the tests could lead on to the skewing of the general positivity rate of the test, a measurement that’s one among the benchmarks utilized in the reopening guidelines released by the White House and CDC.
“I suspect it’ll artificially lower the percent positive,” Caitlin Rivers, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, told NPR.
The White House’s guidelines say that for a state to reopen it must observe a downward trajectory in its number of daily cases or its percentage of positive cases.
The CDC obtains testing data from several sources, including state public health labs, commercial testing companies and hospitals. Officials are working to develop standardized criteria to alleviate complaints about confusion about reporting requirements.