Following transplant at day 72 my husband's FLC assay is normal kappa, lambda and ratio in the serum.
However it is elevated at kappa 5.1 and ratio 12.6 in the urine.
How can the serum, which is supposed to be more accurate, be normal?
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blair77 - Who do you know with myeloma?: My husband
- When were you/they diagnosed?: April 2013
- Age at diagnosis: 43
Re: Free light chain (FLC) results - serum vs. urine
You may find this of interest
http://bloodjournal.hematologylibrary.org/content/109/8/3611.full
Title: "The serum-free light chain assay cannot replace 24-hour urine protein estimation in patients with plasma cell dyscrasias"
Excerpts:
We explored the relationship between proteinuria and SFLC in 174 samples from 135 patients with myeloma. Patients were at varying stages of the disease and therapy, ranging from initial presentation to remission after therapy to relapse ...
As Table 1 shows, higher amounts of total and monoclonal proteinuria were more likely to be associated with abnormal ratio. However, more than 40% of patients with more than 500 mg urine protein per day had normal ratios, suggesting that reliance upon the ratio as a substitute for 24-hour urine collection would have resulted in missing clinically significant proteinuria in a substantial number of patients. In addition, one-third of patients with small amounts of monoclonal protein in the urine had normal ratios.
http://bloodjournal.hematologylibrary.org/content/109/8/3611.full
Title: "The serum-free light chain assay cannot replace 24-hour urine protein estimation in patients with plasma cell dyscrasias"
Excerpts:
We explored the relationship between proteinuria and SFLC in 174 samples from 135 patients with myeloma. Patients were at varying stages of the disease and therapy, ranging from initial presentation to remission after therapy to relapse ...
As Table 1 shows, higher amounts of total and monoclonal proteinuria were more likely to be associated with abnormal ratio. However, more than 40% of patients with more than 500 mg urine protein per day had normal ratios, suggesting that reliance upon the ratio as a substitute for 24-hour urine collection would have resulted in missing clinically significant proteinuria in a substantial number of patients. In addition, one-third of patients with small amounts of monoclonal protein in the urine had normal ratios.
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dnalex - Name: Alex N.
- Who do you know with myeloma?: mother
- When were you/they diagnosed?: 2007
- Age at diagnosis: 56
Re: Free light chain (FLC) results - serum vs. urine
Hello from Seattle on a foggy wet Saturday morning!
The serum free light chain assay has been around for a numbr of years and has been validated in a number of studies. The correlation of serum free light chain results to disease status is accepted for research studies and in routine clinical use.
The use of free light chain assays in the urine, on the other hand, has not been studied extensively and is not used for most research studies or in routine clinical practice, because its interpretation has not been clarified or accepted as of yet.
The short answer is that urine free light chain results are currently not recommended to be used to follow multiple myeloma patients. I do not know why his oncologists ordered the test of course -- perhaps out of curiosity or a special interest?
The serum free light chain assay has been around for a numbr of years and has been validated in a number of studies. The correlation of serum free light chain results to disease status is accepted for research studies and in routine clinical use.
The use of free light chain assays in the urine, on the other hand, has not been studied extensively and is not used for most research studies or in routine clinical practice, because its interpretation has not been clarified or accepted as of yet.
The short answer is that urine free light chain results are currently not recommended to be used to follow multiple myeloma patients. I do not know why his oncologists ordered the test of course -- perhaps out of curiosity or a special interest?
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Dr. Edward Libby - Name: Edward Libby, M.D.
Beacon Medical Advisor
Re: Free light chain (FLC) results - serum vs. urine
Thank you Dr. Libby!
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blair77 - Who do you know with myeloma?: My husband
- When were you/they diagnosed?: April 2013
- Age at diagnosis: 43
Re: Free light chain (FLC) results - serum vs. urine
I also wanted to add that he has IgA lambda myeloma and the elevated level was Kappa and the lambda level was normal! Ugh this disease is so confusing and I feel like we are always trying to figure out tests etc on our own because his doctors never explain anything!!!!
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blair77 - Who do you know with myeloma?: My husband
- When were you/they diagnosed?: April 2013
- Age at diagnosis: 43
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