Virus Tests Will Get Tighter Oversight After Accuracy Issues

(Bloomberg) -- Blood tests that can tell whether patients have been infected with the new coronavirus will get tighter oversight from U.S. health regulators, after some manufacturers made allegedly false or inappropriate claims and questions arose about the accuracy of some of the tests.

The Food and Drug Administration said Monday that makers of the tests, which since mid-March have been allowed to be sold without any government sign-off, will have to apply for authorization within 10 days of their products coming to market. The FDA also laid out requirements tests must meet to gain clearance.

While the FDA’s original March 16 policy was meant to provide flexibility, “flexibility never meant we would allow fraud,” the health agency said in a statement announcing the policy change. “We unfortunately see unscrupulous actors marketing fraudulent test kits and using the pandemic as an opportunity to take advantage of Americans’ anxiety.”

The FDA has given emergency authorizations to 12 antibody tests and said that more than 250 are currently in the review process. The vast majority of the tests currently on the market haven’t been checked by the FDA before being sold.

The antibody tests are considered an important part of the disease surveillance efforts public health authorities are counting on to help roll back social distancing measures and fully comprehend the U.S. outbreak. But as more tests have become available, the agency is beginning to once again tighten its oversight of them.

“High-quality antibody tests or serologic tests can help us understand a person’s and a population’s exposure to Covid-19,” FDA commissioner Stephen Hahn said on a call with reporters. “When we when we issued our original serologic test policy in mid-March, it was critical for the FDA to provide regulatory flexibility for serologic test developers, given the nature of the public health emergency and an understanding that the tests were not to be used as the sole basis for Covid-19 diagnosis.”

The tests can identify previous infections, giving a picture of how many more cases of the virus to expect in the future, as well as how deadly the virus really is. They’re also complex to develop, however, and can be prone to false positives, unwittingly identifying antibodies to other closely related viruses. It’s also still unknown whether the presence of antibodies means a person is immune to the virus, and for how long that immunity might last.

Such details have not stopped some companies from marketing tests directly to consumers. The agency said that it has taken action against companies marketing tests that claim they can be used at home or falsely claim that they have received agency authorization. The FDA said it has required some tests to be removed from market and referred others for criminal investigation. It has also detained fraudulent test kits being imported into the U.S.

Tricky Science

The nature of antibody tests and the speed at which many were developed has resulted in uneven quality, according to one analysis.

A consortium of California scientists studying the accuracy of the tests analyzed 14 antibody tests to find that only three produced consistently reliable results. A similar assessment effort is underway from the Center for Covid Innovation at Harvard University’s Massachusetts General Hospital and Brigham and Women’s Hospital.

“This was desperately needed” said Eric Topol, director of the Scripps Research Translational Institute, of the FDA’s actions on Monday.

Several studies that use antibody tests to survey local populations have indicated that the virus may be far more widespread than current data suggests.

A Stanford University study of Santa Clara County, California, concluded that there had been at least two times as many Covid-19 cases as the county’s official counts, though the authors later revised their study to conclude some 2.8% of the county had been exposed to the virus. A major critique of that study was that its authors put too much stock in the test’s accuracy.

A study by New York state, meanwhile, found 21% of New York City residents had Covid-19 antibodies. The U.S. National Institutes of Health has also announced it will test 10,000 healthy volunteers for the presence of antibodies.

Acknowledging issues of accuracy, last week the White House suggested the use of two antibody tests at the same time. The use of two tests would allow for the results to be checked against each other, improving the chance of a correct result.

The FDA said that tests currently on the market without authorization would have to undergo the authorization process; already more than 100 have begun conversations with the agency. Those emergency authorizations expire once the national coronavirus emergency has been declared over.

©2020 Bloomberg L.P.