[smarty]

Difference - serum total FLC ratio & free FLC ratio?

by smarty on Tue Jul 28, 2015 6:51 pm

I cannot find anything explaining the difference in the

"Monoclonal Protein Blood with Interpretation - Details" which gives my

MPA Kappa, Serum = 2080,
MPA Lambda Serum = 170 mg/dL
Ratio = 12.24

and "Kappa/Lampda, Free , Serum - Details"

Kappa Free, Serum = 38.6 mg/l,
Lambda Free, Serum = 7.0 mg/l
K.L Ratio, Serum = 5.51

My doctor said the first is a total K/L and the second is the one that counts. Interestingly, 3-months ago the tests produced almost identical ratios. I'm just entering smoldering, no symptoms.

I would appreciate any explanation available. Thank you all for all I have learned by the Beacon.

Marti

[JimNY]

Re: Difference - serum total FLC ratio & free FLC ratio?

by JimNY on Tue Jul 28, 2015 8:33 pm

Smarty,

Sorry that you are confused about these tests.

As Cheryl G mentioned to you in an earlier forum discussion,

Immunoglobulins (IgA, IgG, IgM, etc.) are a combination of heavy and light chains. Free light chains are light chains that are not attached to heavy chains. When you measure TOTAL light chains, whether kappa or lambda, you are measuring both FREE light chains and those that are BOUND together with heavy chains in immunoglobulin molecules in your blood or urine. You are also measuring both MONO­CLON­AL (unhealthy / MGUS- and myeloma-related) and POLYCLONAL (healthy) light chains."

What she said is true for light chains anywhere, whether they are in the urine or blood. Does that clear up the difference for you? If not, let me know, and either I or someone else here will try to explain it further.

Also, as Dr. Valent mentions in this earlier forum discussion, and as you will hear often here in the forum, it's really the serum (blood) free light chain test results that you really want to focus on in terms of monitoring myeloma:

"Free light chains & total light chains - difference?" (forum disc. started Apr 7, 2015)

Good luck!

[smarty]

Re: Difference - serum total FLC ratio & free FLC ratio?

by smarty on Tue Jul 28, 2015 9:20 pm

Thank you JimNY. I've read your references and believe I understand. I will ask my doctor why he orders the total K/L ratio as seems to have little value. Interestingly my free serum result in January this year was 10.91 and now it is 5.51. I know it can jump around but maybe? a good sign. Thanks to all. Marti