Democratic lawmakers are questioning the accuracy of a number of coronavirus antibody tests seen as crucial to reopening the economy.
The House Oversight Committee sent letters to four companies manufacturing and distributing antibody tests with concerns about their results on Tuesday, after a recent preliminary study of more than a dozen tests found that many were less sensitive than advertised, leaving risks of false negative or positives.
The panel is "concerned that [the Food and Drug Administration] is not conducting substantive review of serological tests that it has allowed on the market and that those tests may not meet a reasonable standard of accuracy," Rep. Raja Krishnamoorthi, D-Ill., the chairman of the panel’s Subcommittee on Economic and Consumer Policy, said in letters to the companies.
Tune into ABC at 1 p.m. ET and ABC News Live at 4 p.m. ET every weekday for special coverage of the novel coronavirus with the full ABC News team, including the latest news, context and analysis.
The panel, which has been investigating how the antibody tests are regulated, requested that the four companies -- Premier Biotech, BioMedomics, Epitope Diagnostics and UCP Biosciences -- turn over data about their tests, any packaging documents for distributors and information on the number of tests ordered and delivered.
Dr. Ping Gao, the CEO of Epitope Diagnostics, told ABC News that his company plans to get in touch with the House Oversight Committee on Friday about its request for information.
He also defended the accuracy of the company's antibody study, arguing that researchers behind the joint University of California, San Francisco-UC Berkeley study mishandled samples and did not perform the test correctly.
"This is a comparison of fresh water versus salt water. Both are water, but the results are different," Gao said.
MORE: FDA not doing enough to regulate antibody tests, Democrats sayThe other companies did not respond to messages seeking comment on the inquiry.
Antibody tests have been seen as one of several tools that can be used to help reopen the economy, even amid questions about their accuracy.
New testing guidance released by the White House on Monday said the federal government would continue to support the development of the tests as part of the process of reopening the country. And a recent survey of New Yorkers found that one-in-five city residents carried antibodies to the coronavirus.
However, the World Health Organization said in a memo last Friday that there is no definitive proof that people who have been previously exposed to coronavirus could not get infected again.
In the United States, more than 100 antibody tests are currently on the market, most sold without prior FDA authorization. Eight serology tests have been authorized by the FDA under emergency use authorization as of this week.
Developers can sell their tests without prior review in March, as long as they promise to validate their tests, notify the FDA and market them with appropriate disclaimers. The agency has also issued a warning to health care workers not to overestimate their promise.
MORE: A reality check on antibody testing: How do we race forward thoughtfully?"Be aware that not all marketed serological tests have been evaluated by the FDA," the agency wrote last week.
Administrator Stephen Hahn has defended the process put in place make tests available and certify their accuracy.
"We issued some guidance to provide regulatory flexibility," he told NPR on Tuesday. "As typical in a -- or usual in an emergency, a public health emergency, it's striking a balance between making sure the resources are there -- in this case antibody testing -- with, of course, wanting to make sure that these are accurate, reliable and reproducible tests."
Hahn said at the White House last Friday that the FDA is working with other federal health agencies to validate tests sent to the agency, and will provide "as much information as we possibly can" about their efficacy.
Democrats have expressed frustration with the agency’s validation efforts, noting in a letter to Hahn on Tuesday that regulators have only received a handful of the more than 100 tests on the market, and had not yet validated their efficacy.
"It is the FDA’s job to protect the public health. Abdicating that responsibility and trusting private industry to regulate itself is unacceptable," Krishnamoorthi wrote in a letter.
This report was featured in the Wednesday, April 29, 2020 episode of "Start Here," ABC News’ daily news podcast.
"Start Here" offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, Spotify, the ABC News app or wherever you get your podcasts.