Ordering Recommendation

Aid in the monitoring of patients with urinary monoclonal proteins (Bence Jones protein).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

24-hour urine. Refrigerate during collection. Also acceptable: Random urine and urine supernatant.

Specimen Preparation

Transfer 1 mL aliquot from a well-mixed 24-hour collection to an ARUP Standard Transport Tube. (Min: 0.5 mL)

Storage/Transport Temperature


Unacceptable Conditions

Record total volume and collection time interval on transport tube and test request form.


Ambient: Unacceptable; Refrigerated: 3 weeks; Frozen: 6 months


Quantitative Immunoturbidimetry




1-3 days

Reference Interval

Test Number
Reference Interval
  Free Urinary Kappa Light Chains 0.00 - 32.90 mg/L
  Free Urinary Kappa Excretion/Day Refer to Report
  Free Urinary Lambda Light Chain 0.00 - 3.79 mg/L
  Free Urinary Lambda Excretion/Day Refer to Report
  Total Protein Less than 150 mg/d

Interpretive Data

Results of urine free light chain testing can be used to monitor disease progression or response to therapy in patients for whom urine electrophoresis is unable to provide reliable Bence Jones Protein quantification. The results of urine kappa and lambda free light chains must be interpreted in conjunction with urine immunofixation. The free light chain quantitative values may be misleading in specimens with high levels of urinary polyclonal free light chains, and absent Bence Jones protein by immunofixation; therefore correlation with urine immunofixation is required to identify inconsistent results.
Total Urinary protein is determined turbidimetrically by adding the albumin and kappa and/or lambda light chains. This value may not agree with the total protein as determined by chemical methods, which characteristically underestimates urinary light chains.

Undetected antigen excess is a rare event but cannot be excluded. Free light chain results should always be interpreted in conjunction with other clinical and laboratory findings.

Compliance Category



Hotline History


CPT Codes

84156; 83521 x2


Component Test Code* Component Chart Name LOINC
0050565 Total Protein 2889-4
0050683 Free Urinary Kappa Light Chains 38176-4
0050684 Free Urinary Kappa Excretion/Day 38177-2
0050685 Free Urinary Lambda Light Chain 38178-0
0050686 Free Urinary Lambda Excretion/Day 38169-9
0097110 Total Volume 19153-6
0097111 Hours Collected 30211-7
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Free Urine Kappa/Lambda
  • Urine Kappa/Lambda FLC
Free Light Chains, Quantitative, Urine