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
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 |
KTLCU, LTLCU: Nephelometry
Immunoglobulin Light Chains
Kappa Light Chains
Lambda Light Chains
Light Chains, Kappa and Lambda
Urine Light Chains
Urine
If serum is being submitted on the same patient for FLCP / Immunoglobulin Free Light Chains, Serum; order that test under a different order.
Submit only 1 of the following specimens:
Specimen Type: Random urine
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 1 mL
Collection Instructions: Collect a random urine specimen.
Specimen Type: 24-Hour urine
Supplies: Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube
Specimen Volume: 1 mL
Collection Instructions: Collect urine for 24 hours.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens in Special Instructions for multiple collections.
Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.
Ambient | OK <72 hours |
Refrigerate | Preferred |
Frozen | OK |
50% Acetic Acid | No |
Boric Acid | No |
Diazolidinyl Urea | No |
6M Hydrochloric Acid | No |
6M Nitric Acid | No |
Sodium Carbonate | No |
Thymol | No |
Toluene | No |
0.5 mL
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 7 days | |
Frozen | 20 days | ||
Ambient | 72 hours |
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
Immunoglobulin light chains are usually cleared from blood through
Current laboratory procedures employ protein electrophoresis and
Just as quantitative serum immunoglobulins by immunonephelometry
KAPPA TOTAL LIGHT CHAIN
<0.9 mg/dL
LAMBDA TOTAL LIGHT CHAIN
<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 monoclonal kappa light chains.
A K/L ratio less than 0.7 suggests the presence of monoclonal lambda light chains.
In 24-hour specimens, a greater than 90% increase in concentration suggests progression or relapse; a greater than 90% decrease suggests treatment response.
Increased kappa and/or lambda light chains may be seen in benign (polyclonal) and neoplastic (monoclonal) disorders.
Unlike the electrophoretic M-spike, this immunoassay quantitates
The quantitation of urine kappa light chain by immunonephelometry
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.
1. International Myeloma Working Group. Criteria for the
2. Rajkumar SV, Kyle RA: Multiple myeloma diagnosis and
3. Snyder MR, Clark R, Bryant SC, Katzmann JA: Quantitation of urinary light chains. Clin Chem 2008;54(10):1744-1746
In this Siemens Nephelometer II method, the light scattered onto the antigen-antibody complexes is measured. The intensity of the measured scattered light is proportional to the amount of antigen-antibody complexes in the sample under certain conditions. If the antibody volume is kept constant, the signal behaves proportionally to the antigen volume.
A reference curve is generated by a standard with a known antigen content on which the scattered light signals of the samples can be evaluated and calculated as an antigen concentration. Antigen-antibody complexes are formed when a sample containing antigen and the corresponding antiserum are put into a cuvette. A light beam is generated with an LED, which is transmitted through the cuvette. The light is scattered onto the immuno-complexes that are present. Antigen and antibody are mixed in the initial measurement, but no complex is formed yet. An antigen-antibody complex is formed in the final measurement.
Monday through Friday
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.
83883 x 2
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
TLCU | Immunoglobulin Total Light Chains,U | 44792-0 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
KLTRU | Kappa/Lambda TLC Ratio, U | 33559-6 |
KTLCU | Kappa Total Light Chain, U | 27365-6 |
LTLCU | Lambda Total Light Chain, U | 27394-6 |