What The Hell Is An Antibody Test, And Should I Get One?
by Marissa Pomerance
Though most of us have been quarantining for 6 weeks or more, there’s so much we’re still learning about this virus. How it spreads, if we can get it from our groceries (unlikely), and if all of the much-discussed treatments will actually work (there’s some hope!). And just like the confusion surrounding diagnostic testing, the new phase of antibody testing has been similarly opaque. Could it be the key to reopening the economy? Are they accurate? Should we even voluntarily subject ourselves to in-person blood tests right now?
The hype around antibody tests is simultaneously dubious and promising. But as they become more widely available and we weigh the pros and cons of putting ourselves at risk to get one, we wanted to know what they do, if they work, who should get them, and where they’re available.
Let’s dive in.
Umm, What IS An Antibody Test, Though?
Let’s be clear; antibody tests are NOT the same as the diagnostic coronavirus tests (you know, those nose swabs that men claim are painful). Whereas diagnostic tests can only detect a current infection, antibody tests check your blood to see if you’ve been previously exposed to the coronavirus, and if you might have any potential immunity now.
Antibodies are proteins in the blood that are produced as a response to viruses and bacteria, and are used by the immune system to fight these pathogens. Antibody blood tests, also called serologic tests, look for antibodies in the blood. A positive test result means that you do have antibodies, in which case, you’ve likely had a recent coronavirus infection (whether or not you had symptoms), or you still have it now.
A negative test result means that you don’t have any antibodies, which may suggest that you haven’t been infected, or that your antibodies simply haven’t developed yet from a recent infection. As it can take up to 1-3 weeks after infection for antibodies to be present in your blood, the test might not be able to determine if you’ve been infected within the last few days. A negative result, therefore, doesn’t rule out the possibility of a current coronavirus infection from a recent exposure, and it doesn’t mean you’re not potentially contagious.
So while the antibody test might be able to detect an active infection, The CDC still suggests that “serologic tests should not be used as the only way to diagnose someone as being currently sick with COVID-19.” So if you have Covid-19 symptoms, you should get the diagnostic test instead.
Antibody Tests Are Important, But Far From Perfect
Antibody testing is important. Widespread testing can indicate how the disease has spread, how much of the population has been infected, who is immune, and how long that immunity lasts for. Antibody tests can also give a more accurate picture of the overall infection rate and the overall death rate.
But, there is a debate raging over the accuracy of antibody tests, and that debate is multi-pronged. The first problem is timing. As we mentioned earlier, the test might not detect a current or very recent infection if antibodies haven’t developed yet, so gauging the exact timing and contagiousness of coronavirus from an antibody test is tricky.
The second problem is that it’s still too early to determine how much immunity these antibodies provide. The antibodies produced by viruses and diseases all come with different rates of protection, which is why some vaccines last a lifetime, while others need to be distributed every year. Unfortunately, the effectiveness of antibodies is only clear after extensive study, and as of now, for the coronavirus, “it’s unclear if those antibodies can provide protection (immunity) against getting infected again. This means that we do not know at this time if antibodies make you immune to the virus.” So a positive antibody test might confer some protective immunity, but the scientific community doesn’t yet know how much immunity or how long it lasts, and we have a long way to go before we can start issuing “immunity passports.”
The biggest problem with the antibody test, though? As of now, many are simply ineffective. A race to produce these tests as quickly as possible and relaxed federal standards have produced tests that, are so far, unreliable. The FDA has allowed more than 120 tests to go to market without agency review or oversight, but they’ve only issued official authorizations (known as an “EUA”) to a small handful of tests. Consequently, the market has been flooded with tests, and many of these tests are producing false positives or missing infections all together. Some tests are just straight up fraudulent. Health officials are urging consumers to be particularly weary of rapid tests, like fingerprick tests, which claim to provide results within minutes.
But, they’re not all useless. Some are very accurate, and there are legitimate, well-respected labs providing tests. And as we mentioned, the FDA is reviewing the data for some of these tests at least, approving only a select few so far.
Ok, But Should I Still Get It?
Since there is still so much we don’t know about the antibody tests, they should not be used to justify going about life as usual. And they’re not necessary for everyone. The CDC says “the test is generally intended for people who either have had a positive test for Covid-19 and have recovered; or who think they were exposed to Covid-19 and no longer have symptoms.”
This is who should get the test:
People recovering from an active coronavirus infection: If you’re getting over a coronavirus infection and no longer show symptoms, you can get a test to determine if you have some protection against another infection. If your test is positive, you might even be able to donate plasma, which is being studied as a treatment for actively ill patients.
Asymptomatic carriers: If you think you might have been previously exposed to the virus, but haven’t shown any symptoms, an antibody test can confirm whether you’ve been exposed, and if you have some immunity now.
These tests are NOT intended for anyone currently experiencing coronavirus symptoms. The CDC is specifically asking people with symptoms to get a diagnostic test instead.
Where Is It Even Available?
Though antibody tests have apparently flooded the market, it seems we haven’t been given much information about how and where to get one. A quick Google search is similarly confusing, producing ads for little-known testing sites or articles warning you against the antibody test. Of course, you can always call your doctor for a recommendation, but if you don’t have a dependable doctor, you can now get a test from established labs, like Quest Diagnostics.
Currently, the easiest places to get the test are:
Quest: Quest, specifically, has begun offering tests without a doctor’s referral in 2,200 labs across the country, requiring only a simple online sign-up. They’re using tests made by Abbott, which received one of the FDA’s limited EUA’s and are said to be 99% accurate, as well as tests by Eurominn, which are said to have 98.5% accuracy. The test costs $119, and takes about 1-2 days to receive results.
LabCorp: LabCorp is offering tests to patients at 2,000 of its locations. Currently, the tests are free, but only available through a healthcare provider or doctor’s referral. Results are available within 1-3 days. Their tests have not been reviewed by the FDA.
Ok, so antibody testing isn’t exactly perfect. Yet. But that doesn’t mean we should easily dismiss it. Even though it feels like we’ve been quarantining for approximately 4.5 years, remember—we’re still in the early phases of this crisis. Like anything else that’s new and scary, we’ll see flaws and mistakes in the beginning, but hopefully, these tests will become more accurate as we gain more knowledge about the virus, antibodies, and tests themselves. And over time, they can provide us real insight into how this disease spreads, how many it kills, and how we can reach herd immunity.
Marissa Pomerance is the Managing Editor of The Candidly. She’s a Los Angeles native and lover of all things food, style, beauty, and wellness. You can find more of her articles here.
