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HelpTest ID TLCU Immunoglobulin Total Light Chains, Urine
Useful For
Monitoring patients whose urines demonstrate 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
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| KTLCU | Kappa Total Light Chain, U | No | Yes |
| LTLCU | Lambda Total Light Chain, U | No | Yes |
| KLTRU | Kappa/Lambda TLC Ratio, U | No | Yes |
Special Instructions
Method Name
Nephelometry
Reporting Name
Immunoglobulin Total Light Chains,USpecimen Type
UrineIf serum is being submitted on the same patient for FLCP / Immunoglobulin Free Light Chains, Serum; order that test under a different order.
Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
Neurology Test Request Form-General (T732) (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)
Hematopathology/Cytogenetics Test Request Form (T726) (http://www.mayomedicallaboratories.com/it-mmfiles/hematopathology-request-form.pdf)
Submit only 1 of the following specimens:
Specimen Type: Random urine
Container/Tube: Plastic, 10-mL urine tube (T068)
Specimen Volume: 1 mL
Collection Instructions: Collect a random urine specimen.
Specimen Type: 24-Hour urine
Container/Tube: Plastic, 10-mL urine tube (T068)
Specimen Volume: 1 mL
Collection Instructions: Collect urine for 24 hours.
Urine Preservative Collection Options
|
Ambient |
Yes <72 Hours |
|
Refrigerated |
Preferred |
|
Frozen |
Yes |
|
6N HCl |
No |
|
50% Acetic Acid |
No |
|
Na2CO3 |
No |
|
Toluene |
No |
|
6N HNO3 |
No |
|
Boric Acid |
No |
|
Thymol |
No |
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 7 days |
| Frozen | 20 days | |
| Ambient | 72 hours |
Clinical 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 Values
KAPPA TOTAL LIGHT CHAIN
<0.9 mg/dL
LAMBDA TOTAL LIGHT CHAIN
<0.7 mg/dL
KAPPA/LAMBDA RATIO
0.7-6.2
Cautions
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.
Day(s) Performed
Monday through Saturday; Continuously until 3 p.m.
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions.CPT Code Information
83883 x 2