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24902 Total Light Chains, Urine (TLCU)

Total Light Chains, Urine (TLCU)
Test Code: TLCUSO
Synonyms/Keywords

Immunoglobulin Light Chains, Kappa Light Chains, Lambda Light Chains, Light Chains, Kappa and Lambda, Urine Light Chains,

Immunoglobulin Total Light Chains, Urine

U TLCUSO

Useful For
Monitoring patients whose urine demonstrates large M-spikes
 
Confirming the quantitation of specimens that show M-spikes by electrophoresis
 
Detecting urine monoclonal proteins and identification of specimens that need urine protein electrophoresis​
Specimen Requirements

Specimen Type

Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​ ​ ​ ​ ​ Submit only 1 of the following specimens​: ​ ​
Urine(24 hours)​ ​Plastic, 10-mL urine tube ​1.0 mL 0.5 mL​
Urine (random)​ Plastic, 10-mL urine tube​ ​1.0 mL ​0.5 mL
Collection Processing Instructions
Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.

​​Urine Preservatives-Collection and Transportation for 24-hour Urine Specimens
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​​ ​​
​Refrigerated (preferred) ​7 days
​Frozen ​20 days
​Ambient ​72 hours
Interference

Unlike the electrophoretic M-spike, this immunoassay quantitates 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 electrophoresis and immunofixation 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.

Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available
Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday​ ​1-3 days
KTLCU, LTLCU: Nephelometry​
Reference Lab
Test Information

Immunoglobulin light chains are usually cleared from blood through the 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 procedures employ protein electrophoresis and immunofixation for the identification and characterization of urine monoclonal light chains, and the monoclonal light chains may be present in large enough amounts to also be quantitated as an M-spike on protein electrophoresis. The electrophoretic 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.

Reference Range Information
Kappa Total Light Chain: <0.9 mg/dL
Lambda Total Light Chain: <0.7 mg/dL
Kappa / Lambda Ratio: 0.7-6.2
Interpretation
A kappa/lambda (K/L) ratio >6.2 suggests the presence of monoclonal kappa light chains.
 
A K/L ratio <0.7 suggests the presence of monoclonal lambda light chains.
 
In 24-hour specimens, a >90% increase in concentration suggests progression or relapse; a >90% decrease suggests treatment response.
 
Increased kappa and/or lambda light chains may be seen in benign (polyclonal) and neoplastic (monoclonal) disorders.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83883 ​2
Synonyms/Keywords

Immunoglobulin Light Chains, Kappa Light Chains, Lambda Light Chains, Light Chains, Kappa and Lambda, Urine Light Chains,

Immunoglobulin Total Light Chains, Urine

U TLCUSO

Ordering Applications
Ordering Application Description
​COM​Total Light Chains, U (TLCU)
​Cerner​Total Light Chains, Urine (TLCU)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements

Specimen Type

Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​ ​ ​ ​ ​ Submit only 1 of the following specimens​: ​ ​
Urine(24 hours)​ ​Plastic, 10-mL urine tube ​1.0 mL 0.5 mL​
Urine (random)​ Plastic, 10-mL urine tube​ ​1.0 mL ​0.5 mL
Collection Processing
Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.

​​Urine Preservatives-Collection and Transportation for 24-hour Urine Specimens
Specimen Stability Information
Specimen Type Temperature Time
​Urine ​​ ​​
​Refrigerated (preferred) ​7 days
​Frozen ​20 days
​Ambient ​72 hours
Interference

Unlike the electrophoretic M-spike, this immunoassay quantitates 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 electrophoresis and immunofixation 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.

Useful For
Monitoring patients whose urine demonstrates large M-spikes
 
Confirming the quantitation of specimens that show M-spikes by electrophoresis
 
Detecting urine monoclonal proteins and identification of specimens that need urine protein electrophoresis​
Reference Range Information
Kappa Total Light Chain: <0.9 mg/dL
Lambda Total Light Chain: <0.7 mg/dL
Kappa / Lambda Ratio: 0.7-6.2
Interpretation
A kappa/lambda (K/L) ratio >6.2 suggests the presence of monoclonal kappa light chains.
 
A K/L ratio <0.7 suggests the presence of monoclonal lambda light chains.
 
In 24-hour specimens, a >90% increase in concentration suggests progression or relapse; a >90% decrease suggests treatment response.
 
Increased kappa and/or lambda light chains may be seen in benign (polyclonal) and neoplastic (monoclonal) disorders.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Report Available
Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday​ ​1-3 days
KTLCU, LTLCU: Nephelometry​
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​83883 ​2
For most current information refer to the Marshfield Laboratory online reference manual.