Interpretation
The serum free light chains assay is useful in the initial work-up of all plasma cell disorders. An increase in kappa or lambda FLC with an abnormal kappa:lambda ratio can indicate excess monoclonal free light chain production .
•In polyclonal hypergammaglobulinemia , both kappa and lambda FLC are increased, with a normal ratio.
•In renal failure , both kappa and lambda FLC are increased, and the ratio may be increased up to 3.1.
•In biclonal gammopathies, both kappa and lambda may be increased with a normal or abnormal ratio.
FLC assays are useful in monitoring of amyloidosis, light chain myeloma, and non-secretory myeloma and multiple myeloma.
FLC levels change rapidly (half-life is a few hours) compared with intact immunoglobulins (half-life is several weeks) making the FLC assay useful for monitoring the response to chemotherapy or other interventions.
Undetected antigen excess is a rare event but cannot be excluded. If free light chains results do not accord with other clinical or laboratory findings, please contact the Protein Lab so that further investigations can be made.
Reference Intervals
|
Minimum |
Maximum |
| Kappa |
3 |
19 |
| Lambda |
6 |
26 |
| Kappa : Lambda Ratio |
0.26 |
1.65 |
Measurement of uncertainty kappa free light chains 15 %
Measurement of uncertainty lambda free light chains 15 %
Variation in results between different laboratories is a recognised phenomenon for this assay. It is recommended that serial monitoring of serum free light chains is performed in the same laboratory.
Test Method
End-point Nephelometry using Siemens BNII nephelometer and The Binding Site "Freelite reagent".
