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Coronavirus antibody tests plagued by accuracy, reliability concerns

Direct-to-consumer marketing has doctors worried
After antibody test
Awaiting antibody test
Posted at 2:18 PM, May 28, 2020
and last updated 2020-05-28 17:23:19-04

LAS VEGAS (KTNV) — Coronavirus antibody tests are still being dogged by questions about their accuracy and reliability.

More and more tests are being rushed to the market, but they still don’t come with guarantees.

Direct-to-consumer marketing campaigns are on the rise as companies court customers who are eager for answers about whether they had COVID-19.

But buyer beware.

We've learned the currently available tests may be premature, even a money grab by commercial labs.

Yumi Yamamoto's older son sits in a LabCorp medical office after a blood draw to test for COVID-19 antibodies. The reason? His younger brother.

"My son was sick early in February," Yumi explains.

Masked up, arm out, her youngest gets ready for his own test.

"I figured the more information we have the better it is."

Her family is not alone.

"I'm convinced that we had it," said Monica Ursua. She and her husband, Brian, believe they had the coronavirus in January after Brian, a convention teamster, built the Samsung booth at CES.

"I would like to get tested for the antibodies," said Brian.

Enter companies like LabCorp.

It's been sending out marketing emails to anyone who's used its services in the past, saying, "Testing is an important part of health and safety, and we want to make it as easy as possible for you to get critical information."

"There's no harm in knowing if we've already had it," Yumi said.

The harm can come in how consumers use the information.

"My recommendation is to not put too much faith in the antibody tests at all at this point," said Dr. Terry Layman, MD, chief medical officer at OurHealth. "Everybody's hoping that the antibody testing will be kind of a holy grail to get back to normal operations and normal day-to-day activities. It should not be used for that at this point."

Dr. Layman says tests have been allowed to come to market without much data behind them.

FDA approval typically requires multiple validation steps with robust data, but coronavirus antibody tests have been rushed under Emergency Use Authorizations, which allow the companies who develop the tests to validate their own data.

"Usually that's limited to 60, 70, 80 patients, where we're normally getting labs validated with 80,000 patients." Dr. Layman explained.

He's skeptical about test results, pointing to what consumers may not see.

LabCorp's website runs deep with disclaimers, warning, "Although having antibodies usually gives immunity from further infection, there is not enough evidence at this time to suggest that people who have antibodies against SARS-CoV-2, the virus that causes COVID-19, are protected against future infections from the virus."

"So even in the future if we determine what level of antibodies are appropriate to give long-term immunity, the testing that's available currently won't give us those answers," said Dr. Layman.

LabCorp's website continues, "Results from this test also will not provide information on whether you can spread the virus to others and is not used as a basis for diagnosis."

"If [the test result] is positive, it does not mean that you are safe to go back into an infectious environment or a workplace without restrictions," said Layman. "It does not mean that you may not pass it on to others. It does not mean you're out of the woods by any stretch of the imagination."

And then, there's a chance the results are just wrong.

"Your test may be positive because you got exposed to a different coronavirus in the past," including, he says, the one that causes the common cold.

LabCorp's website confirms the possibility of a false positive, adding, "Negative results do not rule out SARS-CoV-2 infection, particularly in those who have been in contact with the virus. Follow-up testing with a molecular diagnostic should be considered to rule out infection in these individuals."

"You feel like you're almost driving in a fog," said Yumi. "It's a fog of information and you don't know what's going to hold true or not."

Despite being sure her younger son had COVID-19 after a trip to California earlier this year, the family all tested negative.

"I was hoping that maybe we'd find out there would be some immunity to it. In true reality, that's all I really was hoping for. It almost felt like wanting a golden ticket from Willy Wonka."

Yumi says had her family tested positive, "I would probably be a little bit more lax, to be honest with you. I think that--even though I don't know--it might provide a false sense of security."

For that reason, Dr. Layman says, "I'm not recommending that patients get these tests in general. The one exception is if patients are signing up to be a convalescent plasma donor."

As we've reported, convalescent plasma donations from recovered COVID-19 patients could be used to help treat the critically ill.

Dr. Layman says antibody tests are also good from a public health standpoint to understand the prevalence of the disease in a given population.

From a consumer standpoint, Yumi has found "There's just a whole bunch of too much information and not enough."

LabCorp would not provide an on camera interview, instead sending the following statement:

The serological antibody tests offered by LabCorp are very accurate, are being offered pursuant to Emergency Use Authorizations issued by the FDA, and have been extensively validated by LabCorp. In fact, as of May 19, the Company began making the Roche Elecsys® Anti-SARS-CoV-2 antibody test available to patients. This test provides 99.8 percent specificity, which is greater than previously available antibody tests. This specificity is crucial to determine reliably if a person has been exposed to the virus and has developed antibodies. In addition to the Roche Elecsys® Anti-SARS-CoV-2 antibody test, we have also been making three other FDA EUA IgG antibody tests available. These include:
  • Abbott Architect IgG, EUA issued on 4/26
  • DiaSorin LIAISON IgG, EUA issued on 4/24
  • Euroimmun Anti-SARS ELISA IgG , EUA issued on 5/4

The above tests are all very accurate and have specificity that exceed 99%. All of LabCorp’s serological tests must be ordered by a physician or healthcare provider.

UMC is preparing to start antibody testing May 30.

A spokesperson said doctors there wouldn't talk on camera either as they want to wait until all of the details are finalized before moving forward with an interview.

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