[garryrse]

Lambda free light chain - significant decrease

by garryrse on Sat May 23, 2015 2:51 pm

I went into a maintenance program in January where I was taking 10 mg Revlimid (21 days on, 7 days off). At the start of the maintenance program, my lambda free light chain number was 3.32 (kappa and ratio were normal). The 1st month, the lambda number rose to 9.08. The next month, it went to 14.20. The third month we added 20 mg dex (once per week), and the lambda went to 23.60. We continued on the treatment (10 mg Revlimid, 20 mg dex) into the 4th month.

I just got my most recent "free light chain" results and my lambda number is 1.06.

I am very, very pleased, but I think the lab has made a mistake. I sure hope not, but it seems too good to be true.

It it possible for such a significant drop, and could it be that it has taken a while for the dex to "kick in"?

[Ron Harvot]

Re: Lambda free light chain - significant decrease

by Ron Harvot on Sun May 24, 2015 4:18 pm

A single test does not tell much and could be an aberration. You can request a re-test.

Dex can and does enhance the effects of both Revlimid and Velcade. So the results could be good news. However, to be sure you will need to have it re-run.

[TerryH]

Re: Lambda free light chain - significant decrease

by TerryH on Sun May 24, 2015 4:34 pm

I'm glad Ron responded to your question, garryrse, because I had seen it soon after you had posted, but had forgotten about it.

Ron is right with all the points he makes. The only thing I would is a something a lot more basic: Is there any chance that you had the test done at a different lab, and the new lab is measuring free light chain levels using mg/dL as the units, instead of mg/L?

For example, your lambda FLC levels in the past may have been:

3.32 mg/L = 0.332 mg/dL
9.08 mg/L = 0.908 mg/dL
14.2 mg/L = 1.420 mg/dL
23.6 mg/L = 2.360 mg/dL

So your latest lambda FLC of "1.06", if it's mg/dL, would not look that strange. It would still be a noticeable drop, but not quite so wacky as it seems at first glance.

If there's no difference in units in the lab reports, then I would get another test done.

What's been going on with your M-spike during this time period?

[garryrse]

Re: Lambda free light chain - significant decrease

by garryrse on Tue May 26, 2015 12:48 pm

The lab is the same as has been used in the past, so the measurements are based upon the scale.

In any case, I am going to have the test run again.

Thank you, Ron and Terry, for your responses.

[TerryH]

Re: Lambda free light chain - significant decrease

by TerryH on Tue May 26, 2015 11:19 pm

Hi Garry,

I'm surprised that the units for the test are the same as those used in previous tests. In that case, and assuming you're not seeing any other evidence that backs up a drastic decline in the free light chains – like a big drop in your M-spike – it probably is a fluke.

Let us know what you find out with the repeat test.

[Mike F]

Re: Lambda free light chain - significant decrease

by Mike F on Thu May 28, 2015 12:36 pm

I would go with the re-test as well. I've been getting monthly tests for a couple of years and there was one month in which my kappa light chains went from around 5 to around 50 mg/dl. This seemed weird, as my multiple myeloma is the lambda version. The next test had it back around 5 and I assume that there was a decimal point error in the report that had it at 50. One of the doctors here who responded to my question on this called it "laboma".