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FDA modifies antibody test policy; warns against false results

US to rein in flood of virus blood tests after lax oversight
Posted at 11:50 AM, May 06, 2020
and last updated 2020-05-06 12:50:50-04

WASHINGTON — U.S. regulators are revising a policy that has allowed coronavirus blood tests to reach the U.S. market without first providing proof that they worked, the Associated Press reports.

The move this week by the Food and Drug Administration follows criticism that the lack of oversight created a Wild West of unregulated tests, the AP reports.

Under the new policy, companies with tests kits for sale will be required to submit information on their test's accuracy within 10 days, the AP reports.

The blood tests are designed to show who has had a coronavirus infection in the past and may have some immunity. Most use a finger-prick of blood on a test strip, the AP reports.

The FDA has posted a detailed article about this issue, which you can read here.

According to the article, the FDA early on had allowed unvalidated tests to be used - as long as they were processed by an FDA-approved lab. But some labs were "validating" tests from different manufactures and that was not intended by the earlier FDA policies.

"Moreover, as we have said before, it is not accurate for developers to claim their test was authorized by the FDA if an EUA (emergency use authorization) was not granted for the tests, nor should they be distributing their test if it has not been properly validated," the post states.

The new FDA policy includes these expectations for antibody test developers:

  • Commercial manufacturers will submit EUA requests, with their validation data, within 10 business days from the date they notified the FDA of their validation testing OR from the date of this policy, whichever is later.
  • Furthermore, the FDA has provided specific performance threshold recommendations for specificity and sensitivity for all serology test developers.

But most importantly for citizens, it's important to understand the limits of these tests, the FDA wrote. Even a good test can be wrong more than 50 percent of the time, the post states:

"As important, those who use an antibody test need to understand its limitations and use test results as just one piece of data to inform decision making. All tests can provide at least some false results. Even a high-performing antibody test when used on individuals in a population that does not have many cases of COVID-19 infection – a population with low prevalence – may produce as many or more false results as true results because the likelihood of finding someone who has been infected is very small. This doesn’t mean the test is bad, but rather recognizes the inherent limitations of these kinds of tests. Therefore, it may be necessary for some individuals to have two serology tests performed to generate reliable results. That is why antibody tests should only be used as part of a well-conceived testing plan and why the results should always be interpreted by appropriate experts," the post states.