[Dr. Prashant Kapoor]

Re: Can "false highs" of free light chain tests occur?

by Dr. Prashant Kapoor on Thu Aug 21, 2014 12:27 am

Hello South Dakota,

I am sorry to hear about your pain. Based on the information that you have provided, I am assuming you have IgA kappa monoclonal gammopathy and that all monoclonal studies are being periodically performed in the same laboratory.

Your involved (kappa) free light chain (FLC) appears to have increased slightly (generally, a single-digit increase is considered a small increase). However, the FLC ratio (K/L) has increased considerably because the uninvolved free light chain (in this case lambda) has reduced somewhat.

For interpretation, one has to take into account a number of factors, not just the free light chain levels or ratio.

Usually, the intact immunoglobulin, such as IgA in your case, should be looked at first if it is elevated (and measurable). However, there is a phenomenon called the 'light chain escape' where the plasma cells shift secretion from the intact immunoglobulin to free light chain only. It appears that your IgA levels have also increased slightly.

In addition to the monoclonal protein levels in the serum and urine, the presence of certain symptoms (for example: back pain, bone pain, fatigue, neuropathy, recurrent infections, shortness of breath, swelling, etc) or laboratory abnormalities (anemia, high calcium, elevated creatinine, proteinuria, etc ) should be taken into account to assess for progression.

I agree with your physician's recommendation of monitoring your free light chains a little more closely. Stable levels in the coming months would be reassurring. It would be important to discuss about your pain and other symptoms with your physican.

Thank you for posting your question and follow-up information. Let us know what happens at your next appointment and if you have any additional questions.

[Multibilly]

Re: Can "false highs" of free light chain tests occur?

by Multibilly on Thu Aug 21, 2014 7:56 am

Isn't the light chain escape phenomenon associated with post-treatment multiple myeloma patients that may be relapsing? Can it indeed occur with MGUS and smoldering myeloma patients that haven't undergone treatment?

http://www.thebindingsite.com/lightchainescape

[Dr. Prashant Kapoor]

Re: Can "false highs" of free light chain tests occur?

by Dr. Prashant Kapoor on Thu Aug 21, 2014 11:37 pm

Hello Multibilly,

Light chain escape is typically seen in pretreated myeloma. However, we can see increase in the light chains in MGUS, smoldering myeloma and AL amyloidosis patients without concomitant increase in the intact monoclonal immunoglobulin.

Light chain escape is a marker of sub-clonal evolution, i.e., one group of plasma cells becoming dominant and subjugating or suppressing the surrounding groups. It is therefore important to look at all three monoclonal protein studies (SPEP, UPEP and the free light chains) serially to determine any progression, and not just rely on one.

[Beacon Staff]

Re: Can "false highs" of free light chain tests occur?

by Beacon Staff on Sat Aug 23, 2014 2:25 pm

Thank you, Dr. Kapoor, for the follow-up information about light chain escape. That's a very helpful clarification.

If readers of this thread are interested in general information about light chain escape, there is a posting from Beacon Medical Advisor Dr. Peter Voorhees elsewhere in the forum that answers the question, "What is light chain escape?" (posting by Dr. Voorhees on November 18, 2011).

[Multibilly]

Re: Can "false highs" of free light chain tests occur?

by Multibilly on Sat Aug 23, 2014 2:43 pm

I greatly appreciate the thorough follow-up Dr. Kapoor. Many thanks!