[WholeNotherWorld]

Bence Jones protein level and urine sample size

by WholeNotherWorld on Tue Jul 04, 2017 2:02 pm

Hi,

Love the information and support from this website.

I have a question about interpreting 24-hour urine results. Is there any relationship between the quantity of Bence Jones proteins and sample volume?

For example, if the quanity of Bence Jones went down from the prior test, but so did the volume of urine, what does that mean?

I haven't seen (or I missed it) a discussion of relativity (Bence Jones per volume of output). Or maybe it doesn't matter.

Thanks in advance for your insight.

Happy 4th of July.

[Multibilly]

Re: Bence Jones protein level and urine sample size

by Multibilly on Tue Jul 04, 2017 4:40 pm

WholeNotherWorld,

Regardless of differences in sample volume from test to test, UPEPs are notoriously inaccurate for measuring monoclonal free light chain (Bence Jones protein) levels due to the normal variations folks will have in their renal function, infections, etc. at any given point in time. UPEPs are useful for detecting the overall presence of Bence Jones proteins, renal issues, amyloid protein activity, etc., but I wouldn't put a lot of stock in tracking your Bence Jones protein levels with a UPEP due to their inherent inaccuracy. You are better off tracking your free light chain values with a serum free light chain assay, which is quite accurate. At least, that's what I've picked up on this forum over the years.

Having said all this, I believe most labs distill down the 24 hour urine samples many, many fold before running the electrophoresis and immunofixation tests so that they can easily analyze the entire sample. I also don't think that the overall sample volume makes that much difference in the final measurement accuracy, since your body is excreting roughly the same amount of Bence Jones proteins, regardless of how many fluids you ingest. As long as they are analyzing the entire sample, you are going to end up with the same mass/time (g/24-hour) of Bence Jones proteins in the sample regardless of sample size. But this is something you should really verify with your doctor since I'm just speculating on this point.

[WholeNotherWorld]

Re: Bence Jones protein level and urine sample size

by WholeNotherWorld on Wed Jul 05, 2017 4:57 pm

Thank you Multibilly.

You always post such helpful information. As a 25 year veteran in the medical research industry, I am humbled by the complexity of multiple myeloma, and have embarked on an unplanned retire­ment learning curve that will likely keep me out of trouble for a while!

My husband does also get serum free light chain assays done.

I keep a spreadsheet of the key variable results. It was the spreadsheet that got me thinking about the volume question. Much appreciate your insight.