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Kappa/Lambda Light Chains, Random Urine
Test CodeLAB00476
Alias/See Also
LAB00476
Mayo TC: TLCU - Random and 24 Hour Urine
Mayo Test Name: Immunoglobulin Total Light Chains, Urine
Mayo TC: TLCU - Random and 24 Hour Urine
Mayo Test Name: Immunoglobulin Total Light Chains, Urine
CPT Codes
83883 (x2)
Includes
Kappa Total Light Chain
Lambda Total Light Chain
Kappa/Lambda Total Light Chain Ratio
Lambda Total Light Chain
Kappa/Lambda Total Light Chain Ratio
Preferred Specimen
1.0 mL - Random Urine
Minimum Volume
0.5 mL - Random Urine
Other Acceptable Specimens
1.0 mL from a 24 Hour Urine Collection - Record total volume and duration of collection.
No preservatives.
No preservatives.
Transport Temperature
Refrigerated
Specimen Stability
Refrigerated: 7 days
Methodology
Siemens Nephelometer II - Light scatted onto the antigen-antibody complexes is measured.
Report Available
1-3 days
Limitations
Unlike the electrophoresis M-spike, this immunoassay quantiates both polyclonal and monoclonal light chains and is therefore not sensitive for detecting small monoclonal abnormalities. A normal kappa/lambda (K/L) ratio does not rule out a monoclonal protein, and an abnormal ratio does not identify a monoclonal protein. Urine protein electorphoesis and isotype testing are more sensitive and specific.
The quantitation of urine kappa light chain by immunonephelometry yields results that are approximately 2 times the values from the electrophoresis M-spike. Sequential results should be compared to previous results obtained by the same methodology.
The quantitation of urine kappa light chain by immunonephelometry yields results that are approximately 2 times the values from the electrophoresis M-spike. Sequential results should be compared to previous results obtained by the same methodology.
Reference Range
Kappa Total Light Chains:
<0.9 mg/dL
Lambda Total Light Chains:
<0.7 mg/dL
Kappa/Lambda Ratio:
0.7-6.2
A kappa/lambda (K/L) ratio greater than 6.2 suggests the presence of monocolonal kappa light chains.
A K/L ratio less than 0.7 suggests the presence of monoclonal lambda light chains.
Increased kappa/or lambda light chains may be seen in benign (polyclonal) and neoplastic (monoclonal) disorders.
<0.9 mg/dL
Lambda Total Light Chains:
<0.7 mg/dL
Kappa/Lambda Ratio:
0.7-6.2
A kappa/lambda (K/L) ratio greater than 6.2 suggests the presence of monocolonal kappa light chains.
A K/L ratio less than 0.7 suggests the presence of monoclonal lambda light chains.
Increased kappa/or lambda light chains may be seen in benign (polyclonal) and neoplastic (monoclonal) disorders.
Clinical Significance
Immunoglobulin light chains are usually cleared from blood through renal glomeruli and reabsorbed in the proximal tubules so that urine light-chain concentrations are very low or undetectable. The production of large amounts of monoclonal light chains, however, can overwhelm this reabsorption mechanism. The detection of monoclonal light chains in the urine (Bence Jones proteinuria) has been used as a diagnostic marker for multiple myeloma since the report by Dr. H. Bence Jones in 1847.
Current laboratory practices employ protein electrophoresis and isotype testing for the identification and characterization of urine monocolonal light chains, which may be present in large enough amounts to also be quantified as a M-spike on protein electrophoresis. The electrophoresis M-spike is the recommended method of monitoring monoclonal gammopathies, such as multiple myeloma. Monitoring the urine M-spike is especially useful in patients with light-chain multiple myeloma in whom the serum M-spike is very small or absent, but the urine M-spike is large.
Just as quantitative serum immunoglobulins by immunonephelometry are a complement to M-spike quantitation by serum electrophoresis, this quantitative urine light-chain assay may be used to complement urine M-spike quantitation by electrophoresis.
Current laboratory practices employ protein electrophoresis and isotype testing for the identification and characterization of urine monocolonal light chains, which may be present in large enough amounts to also be quantified as a M-spike on protein electrophoresis. The electrophoresis M-spike is the recommended method of monitoring monoclonal gammopathies, such as multiple myeloma. Monitoring the urine M-spike is especially useful in patients with light-chain multiple myeloma in whom the serum M-spike is very small or absent, but the urine M-spike is large.
Just as quantitative serum immunoglobulins by immunonephelometry are a complement to M-spike quantitation by serum electrophoresis, this quantitative urine light-chain assay may be used to complement urine M-spike quantitation by electrophoresis.
Performing Laboratory
Mayo Clinic Laboratories