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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

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Ordering 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.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

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

Reference Values

KAPPA TOTAL LIGHT CHAIN

<0.9 mg/dL

 

LAMBDA TOTAL LIGHT CHAIN

<0.7 mg/dL

 

KAPPA/LAMBDA RATIO

0.7-6.2

Day(s) Performed

Monday through Friday

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 US 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

Interpretation

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.

Clinical Reference

1. Kumar S, Paiva B, Anderson KC, et al. International Myeloma Working Group consensus criteria for response and minimal residual disease assessment in multiple myeloma. Lancet Oncol. 2016;17(8):e328-e346

2. Leung N, Barnidge DR, Hutchison CA. Laboratory testing in monoclonal gammopathy of renal significance (MGRS). Clin Chem Lab Med. 2016;54(6):929-937

3. Willrich MA, Katzmann JA. Laboratory testing requirements for diagnosis and follow-up of multiple myeloma and related plasma cell dyscrasias. Clin Chem Lab Med. 2016;54(6):907-919

4. Rajkumar SV, Kyle RA. Multiple myeloma: diagnosis and treatment. Mayo Clin Proc. 2005;80(10):1371-1382

Report Available

Same day/1 to 3 days

Method Name

Nephelometry