Is it normal for free light chains to fluctuate?

Posted by nick86 @nick86, Oct 25 9:54am

Hi all, I hope you're all coping okay with whatever life is throwing at you at the moment.
I have IGG lambda MGUS. My M-Spike has remained stable at around 12 g/l (1.2g /dl) since my last blood test 3 months ago. My Lambda light chains have risen from 22.17 to 30.10 in that time. However my free light chain ratio is still within normal range. My Kappa light chains haven't moved. Is it normal for light chains to do this and what happens if it keeps rising?
Best wishes to all.

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My amateur observation is that since you have IgG lambda m protein, that’s the FLC (lambda) that will increase.
But reassuring that your m protein has been stable and your ratio still wnl.
Oddly I have bi-clonal M spikes
( IgG kappa & IgM lambda) but the lambda FLC are higher (54) compared to kappa (21 ) so I think the IgM is maybe dominant? Ratio hasn’t changed in 2 years- get labs in February.
We will see if anything happens and hoping it all stays dormant. 🙏🏻🫣 I feel pretty good.


I do think minor fluctuations such as yours are expected and not a cause for concern.


Thanks so much Leslie. I'm very new to this so I have no idea if the changes are considered large or small. I'm glad you're feeling okay and I hope that all remains stable for you for many many years to come.


IgG lambda here, found on BMB in 2021 (8%). Was slowly increasing for a little over a year, but in the last 9-10months it’s jumped in both IgG level (now over 29g/l), and the lambda level is jumping up to 49mg/l with the k/L ratio being outside low at 0.24. Significantly low in IgA and gamma globulins, which the new haematologist thinks is related to innate deficiency I’ve had since birth (news to me, however it makes sense with the lack of response to many vaccines and multiple long-standing infections as a child). In the last 8-9 months I’ve now got high serum creatinine and eGFR indicating chronic kidney disease (3a), from perfect kidneys (I used to be on the live donor list to give away a kidney, which had rigorous tests to be accepted). The change went from grumbling away with very slow increases, to a big jump in numbers confirmed in July’s tests.
Going to have another BMB in November.
IgG lambda apparently has a propensity for kidney problems – I’d recommend staying on top of your results and asking lots of questions of your haematologist.


I'm really sorry to hear of what you're going through. Thank you for your reply. I will certainly keep on top of my numbers. Next blood test is in December.
I hope the BMB results bring you some better news.
Best wishes.

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