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HelpTest Code LAB5540 Immunoglobulin Total Light Chains, Urine
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Immunoglobulin Total Light Chains,USpecimen 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: 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.
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 7 days |
| Frozen | 20 days | |
| Ambient | 72 hours |
Specimen Minimum Volume
0.5 mL
Special Instructions
Day(s) Performed
Monday through Friday
Specimen Retention Time
14 daysReport Available
Same day/1 to 3 daysReference Values
KAPPA TOTAL LIGHT CHAIN
<0.9 mg/dL
LAMBDA TOTAL LIGHT CHAIN
<0.7 mg/dL
KAPPA/LAMBDA RATIO
0.7-6.2
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
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 |
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 |
Supportive Data
In a study of 168 urine samples with a monoclonal light chain detected by immunofixation electrophoresis (IFE), there were 20 samples with a normal kappa/lambda (K/L) ratio. These samples had either no M-spike (n=13) or M-spikes <0.5 mg/dL. Conversely, among the 148 cases with an abnormal K/L ratio, there were 12 samples with no M-spike indicating that there is no clear M-spike value at which the K/L ratio identifies monoclonal light chains. In patients with an M-spike, the relationship between the kappa and lambda light-chain quantitation and the size of the M-spike had good correlation (kappa, r[2]=0.94;lambda,r[2]=0.71) and the regression lines had slopes of 2.4 of kappa and 1.1 for lambda.
Interestingly, there was a single case in which the K/L ratio was 24 and the free light-chain K/L ratio was 58, but the IFE showed polyclonal light chains. The patient was post-transplant for a kappa light-chain multiple myeloma and presumably had multiple forms of a monoclonal kappa light chain that migrated in a smear and was a false-negative by IFE.