BETA - What is immunofixation (IFE) and why is it an important test?

Blood tests play a big role in keeping tabs on multiple myeloma. They help doctors understand how the disease is behaving, how well treatment is working, and whether any complications are starting to show up. By looking at things like blood cell counts, protein levels, and kidney function, these tests offer important clues about your overall health and how active the myeloma is. In this Health Tree University lesson, we'll focus on one key test, immunofixation. It's a powerful diagnostic tool, and it can provide essential information throughout your treatment journey. Let's take a closer look at how it works and why it matters. What is immunofixation and why is it needed? So we start the first screening for myeloma. The initial diagnostic testing is something called a serum protein electrophoresis. What that does is by electrophoresis, which is by means of applying some electrical charge, basically separates out the protein and shows that there may be an abnormality of monoclonal protein in a specific area. To learn more about the serum protein electrophoresis, S-PEP test, make sure you watch the Health Tree University lesson on this subject in our myeloma-specific blood and urine test course. This is now further looked at with an immunofixation. And immunofixation is a more sensitive way of looking at it. It increases if an S-PEP or a serum protein electrophoresis picks up the abnormality in 80% of cases, the immunofix, one, confirms that there is a monoclonal protein in the area and two, identifies the protein. So it increases the sensitivity from 80% to 90%. It boosts up an extra 10% of patients with this monoclonal protein. It also helps in situations where there is a monoclonal protein, but it's kind of buried in a dense background of polyclonal proteins. So the immunofixation can tease out that monoclonal component with more reliability. Immunofixation is a blood test that is done normally hand in hand with the serum protein electrophoresis. So when we're doing blood tests to try to identify the protein that's being made by the cancer cell, which we call a biomarker, we have a test called serum protein electrophoresis that can identify an abnormal amount of one particular type of protein in the blood. And it's called a spike or an M-spike. But it doesn't tell us what type of abnormal protein it is. It just tells us that there is an abnormal amount of protein and it gives us a quantity for that protein in a numerical value, 3, 2.1, 0.3 or 0. So the immunofixation is going to help give us a name to that protein and tell us if this is an IgA, an IgM, an IgD or an IgG. So it gives us the last name of the type of protein that the cancer cell is making. How does immunofixation identify the specific M protein that is made by an individual's myeloma cell? Once we confirm the presence of a monoclonal protein, we need to know what kind of protein it is. Is it an IgG? Is it an IgA? Is it a kappa or a lambda? And so by applying specific antibodies to these areas of question, the specific protein can be identified. How often should immunofixation be repeated? Once you've identified what the protein is, there's not a specific need to repeat the immunofixation test at every time you're monitoring. We generally do myeloma markers every month, but as the disease is responding and if they have an M spike, then the level of response can be tracked with that serum protein electrophoresis, which tracks the level of the M spike. At some point, what we hope to see is that the M spike is gone and you've been no longer detecting an M spike. But because the sensitivity of the immunofixation test is higher, this would be an important time to do an immunofixation test to see if the protein is still detectable on a more sensitive analysis. It also then will tell us what the degree of response is. There are certain specific categories of response that relies on that immunofixation test. Once the immunofixation test also becomes negative, we are now comfortable that the myeloma is achieving deeper levels of response. And then we can continue to monitor this periodically by doing this at whatever frequency, and that varies with the patient every few months, every couple of months, or whatever, to see if that is making a reappearance. We don't have to do immunofixation every time. We normally will do it at the time of diagnosis so that we can determine which type of protein it is. As patients know, it's quite different if you have IgM, which is very unusual in multiple myeloma versus IgG, et cetera. And we will sometimes do the immunofixation when you want to measure very deep levels of response. So for instance, after stem cell transport, that would be pretty standard that we do that. And that's how we monitor patients with this type of protein markers. You complement this with the other tests, the free light chain and the immunoglobulins. If the immunofixation test indicates there is no detectable myeloma present, what are the next steps? Other tests that we use in myeloma are the free light chain analysis. So sometimes you can have a myeloma that's negative on the serum protein electrophoresis. It's not picking up a monoclonal protein. The immunofix is also negative, but the free light chain ratio is significantly abnormal. So in that case, depending on whether it's a kappa or a lambda, you would call it either a kappa light chain disease or a lambda light chain disease after making sure that other forms of myeloma that are much rarer, like an IgD or an IgE myeloma is ruled out. So these are the different testings that are done on the blood work. Once we find that all of these do not show a myeloma, the myeloma is no longer detectable by any of this testing. And MRD testing is very useful. The best way to do it now is with a next-gen sequencing. One can also do it with an eight-color flow cytometry. And then so by doing this particular testing, we are able to get down to sensitivities of one to the 10 to the minus five or even one in a million cells. So we're picking up one tumor cell in a million cells that we're looking at. So these are very fine technologies that are, if applied in the right way, is very helpful in showing us the level of tumor. How long does it usually take to get the results back from an immunofixation? It really depends on the institution or the lab. Sometimes it's a send-out test and not done locally. So it generally takes somewhere two to five days or so to get those results back. The Immunofixation Electrophoresis, IFE test, is a vital diagnostic tool used to detect and characterize abnormal monoclonal proteins in blood. Its precision makes it essential not only for diagnosis, but also for monitoring disease progression and treatment response. Understanding IFE patterns is crucial for clinicians to make informed decisions in the management of plasma cell disorders. To track your testing results, sign up for a Health Tree account. Once your medical records are connected, you can view your test results by clicking the Track My Disease button on your dashboard. You can also find personalized treatment options and relevant clinical trials based on your profile. 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