Antibody tests are already seen as a critical tool in lifting lock-down measures, because they could potentially be used to figure out who has immunity to the coronavirus. In this case, false positives would be the greater concern, because it could be dangerous to tell someone that they have antibodies and are safe to go back to work when that is a false signal.
There are issues that need to be figured out before rushing to rely on these tests, Stanford’s Pinsky warned. What level of antibodies are needed to mean that someone is protected? And if you are protected, how long are you protected? The answers to these basic questions are still unknown, he said. This week, the World Health Organization put out guidance recommending against using antibody tests for clinical decision making.
The FDA, meanwhile, is lowering the bar even further. On March 16, it issued new guidance allowing manufacturers to distribute tests even before receiving emergency use authorization, for a “reasonable period of time” – about 15 days – after a diagnostic maker had validated the test internally and while preparing its request to the agency for an EUA.
Local governments are desperate enough for tests that they’ll buy them without assurances of accuracy at all. Chicago recently ordered 11,000 antibody tests made in South Korea that had not been reviewed by the FDA but are legal to distribute as long as they include several disclaimers including a recommendation that any negative result be confirmed with a diagnostic test.
“There’s no time really to put the effort into saying, ’Where’s the problem here?’ ” said Catherine Troisi, an epidemiologist at the University of Texas Health Science Center. “I’m not saying the test is bad. But what good is a test if you don’t know it’s giving you reliable results? We just don’t know.”
Correction, April 10, 2020: This story originally said incorrectly that Kendra Boroff was admitted to an intensive care unit.
This article was first published on ProPublica.com.