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Test Code TLCU Immunoglobulin Total Light Chains, Urine

Reporting Name

Immunoglobulin Total Light Chains,U

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Specimen Required

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.

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

Reference Values


<0.9 mg/dL



<0.7 mg/dL




Day(s) and Time(s) Performed

Monday through Friday; Continuously until 3 p.m.

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 U.S. 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 Reference

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

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)

Analytic Time

Same day/1 day

Reject Due To

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

Method Name

KTLCU, LTLCU: Nephelometry

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

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






Secondary ID