Test ID: TLCU
Immunoglobulin Total Light Chains, Urine
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
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 A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
| 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 |
Method Name A short description of the method used to perform the test
Nephelometry
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Kappa Light Chains
Lambda Light Chains
Light Chains, Kappa and Lambda
Urine Light Chains
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
If serum is being submitted on the same patient for FLCP/84190 Immunoglobulin Free Light Chains, Serum; order that test under a different order.
Forms: If not ordering electronically, submit a General Request Form (Supply T239) with the specimen.
Submit only 1 of the following specimens:
Container/Tube: Plastic, 10-mL urine tube (Supply 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 |
Container/Tube: Plastic, 10-mL urine tube (Supply T068)
Specimen Volume: 1 mL
Collection Instructions: Collect a random urine specimen.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 7 days |
| Frozen | 20 days | |
| Ambient | 72 hours |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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 Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
KAPPA TOTAL LIGHT CHAIN
<0.9 mg/dL
LAMBDA TOTAL LIGHT CHAIN
<0.7 mg/dL
KAPPA/LAMBDA RATIO
0.7-6.2
Interpretation Provides information to assist in interpretation of the test results
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.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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.
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.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. International Myeloma Working Group. Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: a report of the International Myeloma Working Group. Br J Haematol 2003;121:749-757
2. Rajkumar SV, Kyle RA: Multiple myeloma diagnosis and treatment. Mayo Clin Proc 2005;80(10):1371-1382
3. Snyder MR, Clark R, Bryant SC, Katzmann JA: Quantitation of urinary light chains. Clin Chem 2008; 54(10):1744-1746
Method Description Describes how the test is performed and provides a method-specific reference
The assay is performed by immunonephelometry. Specific antisera are mixed with patient samples, and the mixture is subjected to a beam of light before and after formation of antigen-antibody complexes. The change in light scatter after complex formation is proportional to the antigen (light chain) concentration.(Siemens Nephelometer II Operations Instruction Manual, 1999)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Saturday; Continuously until 3 p.m.
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83883 x 2
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| KLTRU | Kappa/Lambda TLC Ratio, U | In Process |
| KTLCU | Kappa Total Light Chain, U | 27365-6 |
| LTLCU | Lambda Total Light Chain, U | 27394-6 |
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