COVID-19 antibody tests are here. But can you trust them?

Antibody tests, which show if someone has successfully fought COVID-19, could help people get back to work. But companies are selling them without FDA approval, leading to questions about their accuracy.

COVID-19 antibody tests are here. But can you trust them?
[Photo: Obi Onyeador/Unsplash]

Companies usually turn to the firm PeopleG2 to run background checks on employees. Now, they can use PeopleG2 to buy up blocks of COVID-19 tests to see if workers have developed immunity to the disease.


PeopleG2 is one of several companies that are selling a type of test that detects COVID-19-fighting antibodies in less than 15 minutes. These tests are part of a confusing landscape of antibody tests for sale online, most of which have not been authorized by the U.S. Food and Drug Administration.

A spokesperson for the FDA told Fast Company over email that these tests don’t necessarily need explicit FDA approval as long as they meet certain criteria. In an update published this week, the FDA notes that antibody tests, also called serology tests, are an important facet of identifying people who have overcome the virus. This information can help determine who might be able to return to work and who might be a good candidate for blood donation.

To help these testing efforts ramp up, the FDA is allowing test developers to market and sell their tests once they have followed certain guidance set out by the FDA to assess accuracy and reliability. The tests are only allowed to be administered in a healthcare setting, since at-home testing has not been sanctioned. “The FDA issued this policy to allow early patient access to certain serological tests with the understanding that the FDA has not reviewed and authorized them,” the agency notes.

ToxTest, a company that sells employee drug testing supplies, is among the companies that are currently selling rapid-result antibody blood tests for COVID-19. ToxTest’s tests were created by W.H.P.M. Inc., a company that creates FDA-approved medical devices. On its website the company says that its test is 97.9% accurate, though it has not been reviewed by the FDA. W.H.P.M Inc. also specifies that its test is for “professional use only,” perhaps a designation aimed at deterring non-clinical use. PeopleG2 also sells antibody tests online from several different test purveyors, including Advin Biotech, a company that has been developing rapid diagnostics since 2009.    

Both PeopleG2 and ToxTest are selling packages of 25 antibody tests for between $625 and $650, or roughly $25 per test. Both tests use a finger-prick blood sample and yield results in less than 15 minutes, and neither have FDA approval. The only antibody test the FDA has approved under an emergency use authorization is a test from Cellex Inc.

Despite coming from established companies that appear to be following guidelines, both Assistant HHS Secretary Admiral Brett Giroir and Dr. Deborah Birx, who is coordinating the response to the coronavirus, have expressed concern about unvalidated tests. “Most of them have not been approved by the FDA,” said Giroir during a Wednesday interview on Fox and Friends. “The FDA, CDC, NIH are trying to validate all the tests that are out there that we know about to make sure that they really perform.”


Already, countries in Europe have struggled through a series of antibody tests that don’t work. Still, the FDA may be taking a dual approach of both allowing tests to come on the market under specific guidelines while simultaneously validating tests in order to get testing capabilities out faster. According to Michael Drues, a biomedical engineering expert who is currently consulting companies on applying for the FDA’s emergency use authorization, the FDA is inundated with applications for the emergency use authorization. 

“Is it worse to not have enough diagnostics or a bunch of diagnostics that don’t work or are not that accurate?” he says. 

Is it worse to not have enough diagnostics or a bunch of diagnostics that don’t work or are not that accurate?”

Michael Drues

The antibody tests being sold by PeopleG2 and ToxText also fall under a sort of medical gray area since they don’t neatly fit the FDA’s definition for medical devices—tools used to diagnose, treat, or prevent illness or injury. In the case of workforce testing, a serology test wouldn’t be used to diagnose someone as sick, so much as indicate whether they can return to work. 

“One could easily argue that the FDA has no business regulating it, because it doesn’t fit the definition of a medical device,” says Drues. Still, as the FDA is reviewing these tests, it is likely to crack down on those that don’t pass muster. The agency can issue a warning letter to a company selling tests it deems fraudulent, as it has done for diagnostic tests that have not garnered its approval.

Companies are taking varied approaches to selling their serology tests. BioAmerica, for example, announced a rapid antibody test that it plans to sell for $10, but is waiting to distribute it in the United States until it has FDA approval. Meanwhile, biotech company Advaite has already deployed its antibody test to Chester County Health Department in Pennsylvania. 

“Chester County is fighting the coronavirus crisis on many different fronts, and undertaking the antibody blood test for our essential personnel is another weapon in that fight,” said the Chester County Health Department Commissioners’ Chair Marian Moskowitz in a press release. “We chose to work with Advaite because our evaluations showed that the company’s test kits performed most efficiently and accurately.”


Serology tests play an important role in understanding and measuring community health. During a conversation hosted by the Massachusetts Institute of Technology in March, Stephane Bancel, CEO of Moderna, a company that has a COVID-19 vaccine in Phase I clinical trials in the U.S., commented on how antibody tests will eventually help determine who is ready to go back to work. However, he said, it’s a delicate process.

“We have to understand: If you are positive, how long will it take for you to not transmit the virus anymore?” he said. If someone has developed the antibodies to combat the virus but is still contagious, that person may go on to infect others who haven’t gotten it yet. Antibody tests alone will not be able to determine if someone is still a carrier for the disease.

The FDA is requiring all companies that sell these tests without authorization to alert buyers that results from their antibody tests do not confirm or rule out infection from SARS-COV-2 and that further testing should be done to diagnose COVID-19.

Giroir says the government is currently validating antibody tests and will roll out a national testing plan around antibody tests in the coming weeks.


About the author

Ruth Reader is a writer for Fast Company. She covers the intersection of health and technology.


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