- Name: Kim Nelson
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Sept. 19th, 2013
- Age at diagnosis: 47
- Name: Amelia
- Who do you know with myeloma?: Self
- When were you/they diagnosed?: December 2011
- Age at diagnosis: 52
- Name: Wayne
- Who do you know with myeloma?: Myself, my sister who passed in '95
- When were you/they diagnosed?: 03/09
- Age at diagnosis: 70
- Name: Karen
- When were you/they diagnosed?: December 2010
- Age at diagnosis: 51
The 24 hour urine protein electrophoresis and immunofixation are most useful for those who have "free light chain" myeloma. In other words, their myeloma cells are either making a lot of free kappa light chain antibodies or free lambda light chain antibodies that are not complexed to a heavy chain (IgG, IgA, IgM, IgD, IgE). A patient's myeloma may make free light chain antibodies exclusively, none or hardly any at all, or a combination of intact antibodies (e.g. IgG kappa) and free light chains (e.g. free kappa light chains).
Free kappa and lambda light chains antibodies are not easily picked up by serum protein electrophoresis (at least not until they reach high levels). The 24 hour urine is much better at picking these up.
The serum free light chain test can also be used to measure free kappa and lambda light chain anibody levels and is even more sensitive than the 24-hour urine testing. The serum free light chain testing has allowed us to rely less heavily on the 24 hour urine tests for those with free light chain myeloma. It may be that your doctor is using this test in the place of the urine testing.
Even if your myeloma does not have a significant free light chain component (i.e. is not making much free kappa or lambda light chain antibodies), your physician should "spot check" the serum free light chain test periodically to assess for free light chain escape. This is a phenomenon in which a myeloma stops making an intact antibody and starts producing just the free light chain component of the antibody. For example, an IgG kappa myeloma may evolve into a free kappa light chain myeloma if the IgG portion of the antibody is no longer made. An SPEP alone would not pick this up until late in the game.
I hope this helps. Let me know if you have any other questions.
University of North Carolina at Chapel Hill
Any advice provided in these postings is based on a very limited amount of information. There is no substitute for the care of your oncologist/hematologist. Therefore, all suggestions should be discussed with your treating physician. None of the comments presented here are meant to replace the evaluation of a patient by a knowledgeable physician.
Dr. Peter Voorhees
- Name: Peter Voorhees, M.D.
Beacon Medical Advisor