Is it normal for free light chains to fluctuate?

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.

Hi there Nick86:
Just wanted to check in with you to see how you’re doing. I imagine you’ve had more labs since last time you posted.
Hope things are staying well.
Leslie

It’s common for the FLC to fluctuate and the difference you describe is small. I have lambda FLC MGUS also for 5 years and the levels have bounced around between 25-90 with the K/L ratio fluctuating accordingly, sometimes normal, sometimes low. If the FLC keep increasing in an obvious upward trend, your Dr may recommend a bone marrow biopsy just to check the plasma cell percentage, hoping for under 10%. Most people with MGUS have no problems from it and remain stable. It just should be monitored periodically.

Hi Leslie,

Thanks for your message. Thankfully everything has remained stable so far. My haemotologist has said that I should have blood tests every six months from now on. I'm so grateful that I'm feeling well currently the thing I've found most difficult has been the mental side of things. MGUS is such a strange thing and the uncertainty has been difficult to cope with at times. I just take heart in that things could be a lot worse!
I hope you're doing okay and are feeling well.
Best wishes.

Thanks so much for this.

Every 6 months isn’t bad- you can live a normal life and let this go a bit now. Yes the mental side has been the worst for me!
To summarize my experience:
Surprise MGUS diagnosis from a complete physical and things escalated quickly.
It was surreal.
I immediately got consultations from teaching hospital specialists and got a very different diagnosis ultimately. Was MGUS & low risk for this becoming anything- I’m 65 now.
Eventually I started believing them and allowed myself to exhale…
It’s been 2.5 years since and I’ve struggled to get my mental health back. After another 6 month check up I go to yearly.
I understand the stress this can cause so take care of yourself!
This is a great source of accurate information and calm support.