[Music] how do you measure free light chains when we're measuring these light chains were measuring chains that are unconnected to the heavy chain molecule and again we're looking for an excess of either Kappa or lambda and typically we know that there is some striking abnormality if the amount of Kappa over lambda and usually that ratio is somewhere around and it depends on the lab maybe 0.6 to 1.7 for example if that ratio is above 8 or usually less than 0.125 most people think that that is a significant abnormality that should be investigated one thing it's important to know that people who have kidney problems from any reason whether that might be diabetes or hypertension they often have higher levels of light chains at baseline and we use the ratio that is the difference between Kappa over lambda to help tell us if there is an abnormality and often people who do have a kidney problem or a creatinine level for example that is above one and a half milligrams per deciliter they might have a slight elevation in that ratio but usually it's not significant after everything sort of settles out so the free light chain test is a new test that has been available to myeloma doctors in the past for the past 15 years I'm going to say and it can be done in the urine or it can be done in the blood the blood we call it Sharron free light chain and the Urim and call it urine free light chain and this is an important test that we need to be doing every time somebody has myeloma in combination with all of the other blood markers that we use for myeloma like the S prep and the immuno fixation and quantitative immunoglobulins because there's gonna be a percentage about 25 to 30% that are going to have a negative s prep and a negative M spike when we do the regular s prep and Amina fixation but are going to have a positive light chain and if we overlook that and by the time the patients comes to us they're going to have end organ damage and significant disease so we can easily detect light chains in and the blood and this free light chain case can replace the you pep when we're doing it on a day to day basis and it's a very convenient test that we can do on a monthly basis to monitor response but another interesting thing that free light chains give us the ability to do is that there are occasions that by detecting abnormal free light rings in the blood it can hint us to an early relapse before we actually see that relapse in an aspect so just to have a clear understanding of the difference between an esper and a free light chain that myeloma cell just like the healthy plasma cell is going to be making a protein that is called an immunoglobulin that is going to be released into the blood because the myeloma cell is not completely functional and the mechanism of protein makings that may be altered it might spew out parts of the protein and not the entire protein and that's what's called free light chains we use free light chains and we assemble them to make one whole antibody which is an EM spike and in myeloma cells we can be spewing out both an EM spike and free light chains and that's why it's so important that whenever we do myeloma testing we do the whole spectrum of SPF unification and free light chain assays [Music]