COVID-19 Antibody Tests Proliferate, but What Do They Show?

What your doctor is reading on

APRIL 22, 2020 — Noopur Raje, MD, has been sitting at home for 5 weeks waiting for her COVID-19 test to turn negative so she can get back to work. She’s a cancer specialist ― head of the Massachusetts General Hospital’s Center for Multiple Myeloma ― but Raje says as soon as she’s allowed back to the hospital, she’ll head straight to the front line of COVID-19 caregivers.

“It’s people like us who have to get back in the trenches and do the work now,” she told Medscape Medical News.

“I still will be at risk,” she said. But, having nursed her physician husband through COVID-19 at home until he was admitted to an intensive care unit, she is determined to help in the COVID-19 wards.

“I will be the first one to volunteer to take care of these patients,” she said. “I can’t wait, as I want to give these folks hope. They are so scared.”

Around the world, it’s assumed that she and others like her who’ve recovered from COVID-19 will be immune to the infection.

Some have suggested that with antibodies to the virus coursing through their veins, these survivors might be given immunity passports. They could be the ones to jump-start people’s lives again ― the first to be let out from lockdown, and in healthcare, the ones to head the ongoing battle against this pandemic.

So, there has been a race to develop COVID-19 antibody tests to identify these people.

Circumventing the Usual Clearance Process

To speed up the process, the US Food and Drug Administration (FDA) made a much-criticized move to allow a free-for-all for developers to begin marketing antibody tests that had not gone through the agency’s usual evaluation process. The result was a flood of more than 90 unapproved tests “that have, frankly, dubious quality,” said Scott Becker, CEO of the Association of Public Health Laboratories (APHL), which represents local and state public laboratories.

The APHL spoke out in dismay ― its chief program officer, Eric Blank, decried the “Wild West” of tests unleashed on the public.


“These tests create more uncertainty than before,” said Kelly Wroblewski, APHL’s director of infectious diseases, in a news conference on April 14. “Having many inaccurate tests is worse than having no tests at all.”

The APHL and the FDA, working with the Centers for Disease Control and Prevention and the National Institutes of Health (NIH), have moved quickly into damage control, conducting evaluations of the tests in an effort to distinguish the potentially useful from the useless.

So far, they have succeeded in issuing emergency use authorizations (EUAs) to only four tests, those marketed by Cellex, Ortho Clinical Diagnostics, Chembio Diagnostic Systems, and the Mount Sinai Laboratory.

For all the other antibody tests on the market that do not have an EUA, “They’re trusting that the test developer has done a good job in validation,” Becker said. But there are worrying anecdotes. “Our members have reported that they’ve seen fraudulent marketing…. We’ve seen the FDA clamp down on some companies… [and] a number of cities and health departments have issued warnings because of what they’ve seen,” he added.

In particular, Wroblewski said, some companies are marketing tests for use in physicians’ offices or pharmacies. “Today, there are no serology tests approved for point-of-care settings,” she warned. “We don’t know how to interpret the test results, if the presence of antibodies indicates immunity, how long it will last, or what titer might be sufficient.”

Uncertainty Emphasized

The FDA emphasized the uncertainty about antibody tests in a statement released on April 18.

Although the tests can identify people who have been exposed and who developed an immune response to the virus,

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