Over the past two weeks, we’ve received so many emails asking about COVID-19 antibody testing. Everyone wants to know what’s the deal with it? Who has access? What’s legitimate and what’s not?
The answer is that we don’t know much—yet. Scientists are scrambling to figure out the best tests, and to get them authorized. The problem is that while we wait, many companies are taking advantage of our COVID-19 fears by creating and selling antibody tests that may or may not be the best or most accurate. So, can you get tested and trust that it’s safe and worth your time and money? Here’s our advice, right now, to navigate all that.
Should I Be Getting Antibody Testing?
When it comes down to it, there are more than a few follow-up questions you need to consider when asking if you should be getting COVID-19 antibody testing. Let’s break them down, so you can be more informed when you see testing promotions pop up online.
What kind of sample do I need?
The rapid tests that are available at the hospital to be able to test you for active COVID-19 infections are done by taking a nasal or throat swab. They use a technique called PCR (polymerase chain reaction). But, if you don’t have an active infection, there’s no need to use sputum (a mixture of saliva and mucus) anymore and it’s recommended to switch to blood as a diagnostic tool.
Your body will store a memory to the virus after you’ve had the infection, and antibodies will then be detected in your blood. Blood is necessary to find the COVID-19 antibodies, not just a nasal or throat swab.
What antibodies should I get tested?
Antibodies are the way that your body remembers it was once infected by a foreign invader. Antibody testing is not a new concept—we routinely use it to see if you’ve been exposed to things like Lyme disease or hepatitis, or to figure out if your body still has memory from a vaccine you’ve received (generally called a titer.)
There are three antibodies currently being tested for COVID-19:
- IgM, or our marker of recent or current infection. This is the first antibody to be released for COVID-19, and will be highest within the first 1-7 days of active infection. After this time period, the IgM antibodies will start to fade away.
- As your body fights off an infection, it starts to develop memory to the virus and creates IgG antibodies. We often find that IgG will be elevated for certain infections and possibly stay elevated throughout your life. But here’s what we don’t know yet for COVID-19: While we’re looking for IgG to be elevated as an indicator that you’ve had an infection, will IgG antibodies stick around longer than 1 week? 3 months? 10 years? We just don’t have an answer to that yet. Many government officials are afraid of giving people a false sense of protection if their IgG antibodies come back positive because we simply don’t know how long our protection lasts.
- IgA antibodies are created from infections that occur on our mucosal membranes, which makes it a great antibody to test for respiratory-based (like COVID-19) infections.
Another key note about antibody testing for COVID-19 is that we aren’t looking for the whole virus—we’re looking for its different parts (called antigens). Then we’re attempting to identify if your immune system made an antibody against any one of them. Having one of these antibodies could mean that you’re protected from getting the virus again.
This is one of the limiting factors to the rapid antibody tests you may have read about in The New York Times. They only require a finger prick and are done in a device that looks like a pregnancy test. But due to its simplicity, these tests are only able to look for one type of IgG antigen response and one type of IgM antigen response—and we’re not 100% sure whether or not the test picked up on the right type, or if your immune system mounted a response against a different type of antigen. This weakness of the test could lead to many false negatives—and only time, and more testing, will tell.
What method of testing is the best for antibody testing?
Many companies will use immunoassay testing versus PCR testing for antibodies. PCR is wonderful for rapid, easy-to-use testing like the nasal swabs in the hospitals. You can get answers fast without much room for error. However, PCR is not traditionally used for antibody testing. If you’re considering getting antibody testing, make sure that you’re getting an immunoassay method (like ELISA or Chemiluminescence immunoassay)—you can ask your doctor specifically about that to be reassured.
Finger-stick vs. blood draw?
The world is waiting on a finger-stick method of antibody testing that can detect many aspects (antigens) of the COVID-19 virus. Right now, it’s not being offered. What we have available is a venous blood test, meaning you need to come in to have your blood drawn and sent to the lab. The obvious cons to this more invasive method are that it takes more time to get results. Plus, if you’re asymptomatic but actively contagious, you risk spreading the virus to the healthcare practitioner drawing your blood.
Until the fingerstick method is available for a multi-antigen test, we believe the venous blood method is the best way to get accurate data.
Who has access to testing?
The only antibody testing offered is through a doctor’s order. No companies are allowed to sell directly to you, as the interpretation of these results should be done by a practicing healthcare provider.
Currently, MIMC is offering antibody testing to a limited number of people as we develop protocols for enhanced cleaning and screening of participants. What we currently have available tests for multiple antigens in all 3 antibody subclasses: IgM, IgG, IgA. It has been evaluated by the FDA and has a 97.14% sensitivity, 98.36% specificity for the detection of SARS-CoV-2.
That said, our number one priority is safety for our staff and lowering transmission from possibly asymptomatic carriers to other individuals. If you’re interested in getting antibody testing done, please reach out to us here.
The ultimate question: Should I get tested?
Knowing the immunity status of our community is very important to slowing the transmission of COVID-19. It can also help you personally know the best next steps for your own health. As we learn more about the longevity of protection these antibodies can provide, we can also help inform recommendations to reduce social distancing or return to in-person work.
As long as you’re utilizing the best of the information available in regards to antibody testing methods, we would recommend it to anyone who is interested. You can contact us here to learn more about the testing we’re offering, and to get in on our first rounds of screening. If you choose not to get antibody testing, you can still #flattenthecurve by keeping your immune system steady, washing your hands, and maintaining social distancing and isolation until we’ve passed the peak of COVID-19.