 What's up YouTube? This is Dr. Ali Hader, Interventional Cardiologist. Thank you for stopping by the channel. So what is the deal with COVID antibody testing? What does it tell me? Do I need it? And how good are they? So I've had countless text messages and calls from family and friends all over the United States asking me about antibody testing, whether they should get it. They've seen advertisements about it and they're wondering should they cough up the money that they're getting charged to get this test done. So I figured this would be a good topic for a quick video. First a few things. Let's talk about the basics. What exactly is an antibody? Well an antibody is a protein that's created by your immune systems. This is a protein that is designed to recognize a specific antigen. An antigen is a unique molecule that occurs on the surface of viruses. Each viruses will have its sort of own various antigens and antibodies are designed to recognize a specific antigen. So how it works is when your body is exposed to a particular virus, your body will then produce these antibodies to uniquely identify that virus based on these little antigens on the surface. So that way in the future, if you get reinfected with this, these antibodies are going to quickly be able to recognize it, bind to it, and either neutralize that virus's effect or target that virus to be attacked and sort of cleaned out by your immune system. Think of it as your body's face ID. Now some people may mount a stronger immune response early on and clear out that virus pretty quickly and not really get very much symptoms. However, other people's immune system will not be able to do that and they're the ones that get very sick. Also the ones that are exposed to very high viral loads get overwhelmed and they're also the ones that likely get very sick because their immune system has not had the chance to kind of build up and fight against it. So that's the concept of antibody testing to figure out if your body's actually been exposed to the virus. We can also actually figure out if you've had a recent infection or you've had an older infection and that's based on the type of antibody we can detect. IgM is an antibody that's produced in the acute phase of an illness whereas IgG is an antibody that hangs out long-term and takes a little longer to produce and that would indicate you had the virus longer ago. So this sounds like an attractive thing to figure out, right? If we can find out if I have antibodies against SARS-CoV-2 or COVID-19 that would mean that I've been exposed to it and potentially I wouldn't get infected again in the future. That could also mean that I'm not potentially an asymptomatic carrier or risk for transmitting the virus unknowingly to other people. So these are the potential benefits of this antibody test. Now like many things in life it's not that simple. There's several things to think about. One is how good is this test and how accurate is this test? Does this test actually tell me I'm immune? And then who should actually get tested? And finally what am I going to do with this information? So these are the things we have to keep in mind when we are thinking about antibody tests. Now one of the most important things to remember is not all tests are created equal. Back on March 26th the FDA had very loose rules with antibody testing companies. They essentially allowed any company that was producing an antibody test to have it available to the public. Now the reason they did that was to try to get that test out there and available and accessible to the public without going through a lot of the regulatory red tape so that we would not deprive these tests from getting out into the public. However what ended up happening is it's sort of the Wild Wild West out there when it comes to testing. Almost 200 companies have released some sort of antibody tests out there and a lot of these are complete shit. And why is that? Because frankly there are companies out there that are just trying to make a buck. They're trying to make a profit during this pandemic in any way they can and they're basically targeting people out of fear and that's just plain fraudulent. Now why is there so much variability in these tests? When we're looking at a particular test we have to figure out how accurate that is. Now there's two things we look at the sensitivity and the specificity. Now the sensitivity is the ability of a test to detect the antibody in the blood if it actually exists. So that means reducing the likelihood of false negatives. Now the specificity is the ability of a test to prove that an antibody is truly not in the serum that a negative test is truly negative. And that's trying to reduce the number of false positives. Ideally we want something as high as possible. Over 95% preferable be in the 97 to 99% range for both sensitivity and specificity to be a really good test. And the reality is a lot of these tests are simply not up to par. Now there are a couple of reasons why these tests may be so variable. One is actually how the test is being performed and sort of the robustness of the test itself. The second is the antigen that they're choosing. Remember to figure out if you have an antibody in your system you have to find the antigen that that antibody is going to bind to. So there's several antigens in each virus so if they pick an antigen that's sort of not the right one this could cross react with other antibodies and cross react with other viruses and not make it as good of a test. So these are all important things to think about and unless you've actually had some testing done and validation done we're not going to know. So a lot of these companies sort of pumped out these tests before really getting them validated just to make a buck and that's why things became all out of whack. Now another thing to think about is the type of antibody test. One is a test that's actually going to give you titers. This is a test that's a quantitative test that's going to figure out the amount of antibodies in your system. You may have a low level antibodies or you may have a high level of antibodies. So that can sometimes be important because if someone has only very low level antibodies against a particular virus that may be that they've been exposed to it but it does not necessarily mean they're immune to it. Whereas if you have a high antibody titer that gives you more confidence that you're actually immune. Now the tricky part here is we don't really know where that cutoff is. We don't have enough information yet to figure out what's that cutoff value to figure out if someone's truly immune or not. Of course higher is better but again we're not really sure where that ends up. The second type of test is sort of a positive or negative result. Now these are these sort of point of care tests that can occur with just a finger prick and a small amount of blood into one of those little cassettes and that will sort of give you a line or a marking in the spot that will determine whether you have the antibodies or not. Kind of like a pregnancy test and that can happen in a very short amount of time. Again that particular test does not give you a titer or a value it's just going to tell you positive or negative. It means that you've been exposed to the virus but again the level of antibodies is not reported so whether or not that positivity means immunity we're still not sure. Now the good thing is the FDA is tightening up their restrictions on these companies so now they're mandating you have to have an EUA or emergency use authorization issued by the FDA before any company can have a test that's available. Now out of those almost 200 companies that are out there so far as of this video only 16 have been approved for EUA. I'm going to link below the FDA website that has a list of all those EUA so you can take a look at that if you're thinking about a test. Now the final question is who should really get this and what do we do with the information? Well those are very good questions. Now from an epidemiological standpoint it's important to figure out how many people in the population actually have been infected with the virus that can give us accurate ways to figure out the true mortality rate, hospitalization rate and how many people were truly asymptomatic carriers. Now from an individual standpoint it's a little bit unclear if you out there wanted to go get an antibody test what are you going to do with the information. We'd like to think this helps us figure out who can safely get back to work, get back to school and get back into the community because if you have had positive antibodies that means you've been exposed and potentially you're immune so you have less likelihood of being an asymptomatic carrier and you have less likelihood of contracting a disease. However my argument is what's going to happen if you test negative? Does that mean you're not going to go back to work? You're not going to go back to school? These are the things that we have to think about and again I don't think anybody's really figured out nuances there. I do think it'd be valuable for high-risk situations in people in high-risk jobs such as healthcare workers, people who work in nursing homes and grocery store workers, places where there's a high likelihood of transmission just because of rapid mobility and elderly people and people who are more likely to get sick and very ill but again at the end of the day we're not really sure. Certainly it's a tractor for us to want to know if we have antibodies or not and certainly I would want to know if I'm been exposed to it or not. The important thing to note is we're still not 100% sure if a positive antibody test truly means you're immune especially since some of these tests are not 100% perfect. So these are important things to remember especially as areas are starting to reopen for business and non-essential business are opening, people are getting more mobile, we still have to maintain social distancing, we should continue to wear masks, still aggressive with washing our hands, be extra aggressive with cleanliness and cleaning surfaces etc no matter where we are because again although this pandemic may have passed the first surge it's still going to hang around here for a while. Hopefully there's no second surge but surge or not there's still going to be infections and there's still going to be transmission because it's going to be quite some time until we obtain this herd immunity where enough people have been infected and developed antibodies that the transmission rate is going to slow down. So until that point or until a vaccine comes out continue to be safe whether or not we get antibody testing or not. So again just ask yourself what you're going to do differently with this antibody test result and of course make sure the test you're getting is a reliable one. Thank you again for checking in and we'll see you next time.