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HelpTest Code TLCU Immunoglobulin Total Light Chains, Urine
Reporting Name
Immunoglobulin Total Light Chains,UUseful 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
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 |
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
UrineOrdering Guidance
If serum is being submitted on the same patient for FLCS / Immunoglobulin Free Light Chains, Serum; that test should be ordered under a different order number.
Specimen Required
Submit only 1 of the following specimens:
Supplies:Â Sarstedt Aliquot Tube, 5 mL (T914)
Specimen Type: Random urine
Collection Container/Tube: Clean, plastic urine collection container
Submission Container/Tube: Plastic, 5-mL tube
Specimen Volume: 1 mL
Collection Instructions:
1. Collect a random urine specimen.
2. Refrigerate after collection and send refrigerate.
Specimen Type: 24-Hour urine
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 1 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. No additive needed for preservation.
3. Urine may be kept ambient during the collection period but should be refrigerated within 4 hours of collection completion.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 7 days | |
| Frozen | 20 days | ||
| Ambient | 72 hours |
Day(s) Performed
Monday through Friday
Test Classification
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
83883 x 2
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| TLCU | Immunoglobulin Total Light Chains,U | 44792-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| KLTRU | Kappa/Lambda TLC Ratio, U | 33559-6 |
| KTLCU | Kappa Total Light Chain, U | 27365-6 |
| LTLCU | Lambda Total Light Chain, U | 27394-6 |
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 isotype testing for the identification and characterization of urine monoclonal light chains, which may be present in large enough amounts to also be quantified 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.
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 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.
Report Available
Same day/1 to 3 daysSpecimen Retention Time
14 daysReject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Method Name
KTLCU, LTLCU: Nephelometry