Test Catalog

Test Id : TLCU

Immunoglobulin Total Light Chains, Urine

Useful For
Suggests clinical disorders or settings where the test may be helpful

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
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

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Name
A short description of the method used to perform the test

KTLCU, LTLCU: Nephelometry

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.


Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Immunoglobulin Total Light Chains,U

Lists additional common names for a test, as an aid in searching

Immunoglobulin Light Chains

Kappa Light Chains

Lambda Light Chains

Light Chains, Kappa and Lambda

Urine Light Chains

Specimen Type
Describes the specimen type validated for testing


Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.


OK <72 hours





50% Acetic Acid


Boric Acid


Diazolidinyl Urea


6M Hydrochloric Acid


6M Nitric Acid


Sodium Carbonate






Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the Testing Laboratory

0.5 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 7 days
Frozen 20 days
Ambient 72 hours

Useful For
Suggests clinical disorders or settings where the test may be helpful

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

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.


<0.9 mg/dL



<0.7 mg/dL




Provides information to assist in interpretation of the test results

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.

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
Recommendations for 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

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Method Description
Describes how the test is performed and provides a method-specific reference

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.


The result is calculated by subtracting value of the final measurement from the initial measurement. The distribution of intensity of the scattered light depends on the ratio of the particle size of the antigen-antibody complexes to the radiated wavelength.(Instruction manual: Siemens Nephelometer II, Version 3, Siemens, Inc., Newark, DE, 2008)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Friday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

Same day/1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test


Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their Regional Manager. For assistance, contact Customer Service.

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 instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

83883 x 2

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

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

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports