What To Know About COVID-19 Antibody Testing

by Elaine Roth
Originally Published: 
A health worker takes a drop of blood for the COVID-19 antibody test after at the Diagnostic and Wel...
A health worker takes a drop of blood for the COVID-19 antibody test after at the Diagnostic and Wellness Center on May 5, 2020, in Torrance, California. VALERIE MACON/Getty

So many weeks after the World Health Organization declared COVID-19 a global pandemic, the novel coronavirus that has completely changed the landscape of our lives remains largely a mystery. Answering one question brings a flurry of new ones, and it seems as if once we think we’ve figured out something, the virus comes out with a brand new mystery to keep us on our toes.

Some of the biggest questions surrounding the virus are with respect to immunity and antibodies. Namely, what do the presence of antibodies mean? If someone has antibodies, are they now protected from reinfection? And if so, for how long?

What Is An Antibody Test?

First, what an antibody test isn’t. An antibody test is not a way to diagnose an active infection.

Instead, an antibody test measures the number of antibodies—the proteins made by the body’s immune system to neutralize bacteria and viruses—in the blood and can, in most cases, determine whether a person has been exposed to a particular infection—in this case, COVID-19.

The test is done via a blood draw, and results are usually available within a few days.

What Does It Mean To Have Antibodies?

A health worker takes a drop of blood for the COVID-19 antibody test after at the Diagnostic and Wellness Center on May 5, 2020, in Torrance, California. VALERIE MACON/Getty

The short answer is we don’t know. The long answer is that while antibodies are generally equated with immunity, and we can usually safely assume that when someone has antibodies to a disease, they have at least some short-term immunity. But when it comes to COVID-19, nothing can be assumed.

“We have the expectation that a positive antibody test can be associated with protection against future infections. But since this pandemic has evolved so quickly, the data isn’t yet available to back up this interpretation,” infectious disease specialist Rekha Murthy, MD, vice president of Medical Affairs and associate chief medical officer at Cedars-Sinai said in a press release.

Are The Antibody Tests Reliable?

Unlike with diagnostic testing, which rolled out too slowly for the nation’s demand, antibody testing seems to be rolling out with ease. Antibody tests have flooded the market and the tests are somewhat widely available, and often accessible without a prescription.

But that widespread availability comes with a warning. There are currently at least 120 tests on the market, and only one has been granted emergency approval by the FDA.

The New York Times reported on a study conducted by the COVID-19 Testing Project, a multidisciplinary team of researchers and physicians at UCSF, UC Berkeley, Chan Zuckerberg Biohub, and Innovative Genomics Institute, which found that of the 14 commercial tests they studied, only three were consistently reliable—meaning returned a false positive one percent of the time or less.

On May 4th, the FDA announced plans to tighten the restrictions on commercial testmakers by requiring them to submit data and seek the agency’s emergency use authorization within 10 business days. The agency is recommending testmakers meet specific accuracy thresholds going forward.

Should I Get An Antibody Test?

A health worker process for COVID-19 antibodies after getting the blood from the patient at the the Diagnostic and Wellness Center on May 5, 2020, in Torrance, California. VALERIE MACON/Getty

Yet another question, yet another murky answer. With the tests being largely unreliable, and the results of the tests being largely useless until we have a better understanding of whether antibodies offer a measure of protection against the novel coronavirus, getting an antibody test is a personal choice. It’s a potential high risk (exposure to the virus) and low reward (a test result that you can take with a grain of salt) situation.

“From a public standpoint, certainly we need to test as many people as possible, and the intent is to try to make it available for anyone who wants it,” says Murthy.

Some studies have shown that up to 25% of people infected with COVID-19 may be asymptomatic and that number may be as high as 50%, according to Dr. Anthony Fauci. That means they may have had the virus and not even known. Which is probably why every conversation I’ve had since March 13th –the day my children’s school closed—has at least partially (usually mostly) centered around wondering whether that fever/cough/few days of fatigue and crumminess were simply fever/cough/few days of fatigue and crumminess, or whether those days were actually the days your body successfully fought off a deadly virus?

Large-scale antibody testing could help researchers understand the spread of the disease. The New York Times reported that one in five New Yorkers tested positive for coronavirus, meaning about 2.7 million might have been exposed to the disease without realizing it.

It’s also important to remember that regardless of the result of the test, positive or negative or some uncertain place in between, you should still observe social distancing and wear a mask in public. Too much is still unknown about this disease—with respect to reinfection and risk of infecting others—to assume anything.

My Antibody Test Experience

When antibody testing became available near me, I decided to go for the test. High risk, low reward — but patience has never been my strong suit, and the uncertainty was weighing on my mind. COVID-19 often feels like a vicious, too real game of roulette, wherein a lucky few are spared the worst of the virus, and an unlucky few are struck down for reasons that simply don’t make sense. Once upon a time, I lived a life mired in medical uncertainty, and spent endless nights lying awake hoping luck would be on my side. It wasn’t then, and I desperately wanted to believe it was this time. If the antibody test came back positive, even knowing it was potentially wrong would give me an ounce more of hope that this time we (my children and I) would be lucky, that this time we’d escaped with nothing more than a few days of headaches. That ounce of hope, to me, would be unquantifiable.

My test was negative. That minor bug that swept through my house was probably not coronavirus. Or, it might not have been a bug at all, maybe nothing but anxiety. Or maybe it was coronavirus and my test was faulty.

The truth is, until we understand more about COVID-19, until we understand why some people are asymptomatic and others succumb to the disease, we are all trapped in this place of medical uncertainty. And the best we can do is protect ourselves, our families and our communities, the best we can. Because answers will come. They often do.

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