International MM Working Group guidelines for free light chain testing in MM

March 23 2009 post. Yesterday I received a special edition of the International Myeloma Foundation’s newsletter, “Myeloma Minute,” where I found some interesting details about the serum free light chain (FLC) test.


In September 2008 “Leukemia” published the guidelines developed by the International Myeloma Working Group for serum free light chain analysis in multiple myeloma. The International Myeloma Working Group is made up of 90 leading myeloma researchers from around the world who collaborate on a broad range of myeloma research projects. With a goal to improve myeloma treatment options and diagnostic systems, their work focuses on protocols to provide a more durable remission for myeloma patients while improving quality of life, addressing the needs of both myeloma patients and the physicians who treat them. And the serum-free light chain analysis guidelines are the result of this collaboration.


Serum free light chain assays are capable of detecting free light chains at their normal (non-elevated) levels in the blood. Importantly, these assays can detect mildly increased levels of free light chains even when these levels are undetectable by other means of testing. This means that multiple myeloma could be detected earlier and it is particularly useful in instances when only small amounts of light chains are produced by the myeloma.


The special edition provides a link to more information about serum immunoglobulin free light chain assays:  


The key recommendations from the International Myeloma Working Group’s guidelines are

  • The serum free light chain (serum FLC) assay in combination with serum PEL (serum electrophoresis) and serum IFE (serum immunofixation) is sufficient to screen for pathological monoclonal plasmaproliferative disorders other than AL (light chain amyloidosis) which requires all the serum tests as well as 24 h urine IFE.
  • The serum FLC assay should be measured at diagnosis for all patients with MGUS, smoldering or active multiple myeloma, solitary plasmacytoma and AL amyloidosis.
  • Serial serum FLC ascertainment should be routinely performed in patients with AL amyloidosis and multiple myeloma patients with oligosecretory disease.
  • It should also be done in all patients who have achieved a CR (complete response) to determine whether they have attained a stringent CR.


“Myeloma Minute” also provides a link to the full guideline paper: For obvious reasons, I concentrated on the smoldering, or asymptomatic, myeloma part. It turns out that this FLC test is useful for assessing prognosis for progression in smoldering MM. An abnormal result predicts for higher rates of progression. For other conditions, MGUS and so on, please have a look at the above link.


An important excerpt: the FLC assay is of major prognostic value in virtually every plasma cell disorder, including monoclonal gammopathy of undetermined significance, smoldering myeloma, active myeloma, immunoglobulin light chain amyloidosis and solitary plasmacytoma.


Well, since I haven’t yet gone to the hospital lab for my blood and urine tests (for reasons that I have explained in a previous post), I am going to ask my GP that this test be added to my never-ending, at this point!, list of tests. Hmmm, as it turns out, it may not always be a bad idea to procrastinate…


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