Lawmakers and public health experts are raising alarms about the widespread embrace of blood tests to gauge whether somebody was previously exposed to the coronavirus.
The blood tests have been heralded by state and federal leaders who hope these so-called antibody tests can help guide decisions about when and how to reopen the country by identifying who has been exposed to the virus and may now have immunity even if they have never been diagnosed.
But in the rush to get tests to the public quickly, there are worries that the Food and Drug Administration (FDA) has allowed companies to market tests with little to no oversight, raising the potential for a surge in inaccurate results.
False positives could mislead people into thinking they have already been infected when they have not.
A debate is also being waged about whether these tests currently provide enough useful information in the fight against the pandemic.
A recent report from the House Oversight and Reform Committee found that the FDA allowed a flood of antibody tests on the market without review, resulting in hundreds of flawed tests that are still available for purchase.
The agency has verified and allowed just 10 tests under a formal emergency-use authorization (EUA), while close to 150 are being marketed directly to customers without any review.
Rep. Raja Krishnamoorthi (D-Ill.), chairman of the House Oversight and Reform Subcommittee on Economic and Consumer Policy, told The Hill he thinks FDA was under enormous pressure from the White House to get as many tests on the market as possible.
Krishnamoorthi said he wants the agency to clear the market of all the unauthorized tests, but he said they have yet to do so.
“FDA is doubling down on their policies. It’s dangerous … and we’re going to regret that,” Krishnamoorthi said in a recent interview. “If you have a test kit that gives you a false positive, that person might view it as a green light to engage with other people and relax social distancing, and a consequence is they’ll get sick and get others sick.”
Kelly Wroblewski, director of infectious diseases for the Association of Public Health Laboratories, said she thinks FDA officials overcorrected after being criticized for acting too slowly with diagnostic tests, which measure whether somebody is currently infected.
Wroblewski said the FDA has largely been responsive when outside groups have pointed to fraudulent tests, but she hasn’t heard from the agency about whether its review process is changing.
On April 17, the FDA told providers about concerns surrounding the antibody tests on the market, saying in a notice that it “does not review the validation, or accuracy, data for these tests unless an EUA is submitted.”
The agency also clarified that antibody tests are not meant to diagnose the disease.
The FDA said it is working with the Centers for Disease Control and Prevention, the National Cancer Institute and the National Institutes of Health to allow test manufacturers to have their products independently assessed for accuracy.
“Performance assessments for serological tests will begin soon, and we expect to start seeing results shortly thereafter,” the FDA said.
Leaders are also leaning heavily on the tests to make policy decisions when the science around coronavirus immunity is still unclear.
During a White House coronavirus task force briefing in mid-April, President Trump said the FDA’s authorization of two antibody tests “would support our efforts to get Americans back to work by showing us who might have developed the wonderful, beautiful immunity.”
It is not known yet whether a positive result for antibodies means a person is immune to the disease, and experts caution against making major decisions based on the test results.
“At this point we have to assume [people] are at risk of reinfection, and we are recommending people with antibodies not change their behaviors in any way,” said Mary Hayden, a professor of internal medicine and pathology at Rush University Medical Center in Chicago and a spokeswoman for the Infectious Disease Society of America.
Wroblewski said the antibody tests, even if accurate, could be giving people a false sense of security.
“We might be making some premature decisions about lifting social distancing too early without understanding how immunity works,” Wroblewski said.
Last week, the World Health Organization warned against making any broad policy decisions based on antibody test results.
Still, widespread testing has already started.
In New York, public health officials tested 3,000 residents at grocery stores and big-box retailers throughout the state. In New York City, about 21 percent of participants were found to carry coronavirus antibodies.
The data showed close to 13.9 percent of the population in New York state — about 2.7 million people — had at some point been infected with the coronavirus.
What’s unclear is what officials and the public are going to do with that information.
“In my personal opinion, there’s not a ton of value” yet in antibody testing, said Wroblewski. “It’s not necessarily meant to drive individual decision making yet.”
Tim Schacker, vice dean for research at the University of Minnesota Medical School, said as long as the public understands the limitations of antibody tests, they can still be useful.
“These are still early days,” Schacker said.
“We will have good data soon but we don’t yet. I just think we are in a learning curve,” he added. “We are in the middle of it with new tests, so we are learning what exactly they mean and how to interpret them.”