Free Light Chains, Quantitative, Urine
Test Mnemonic
UFLCKL
CPT Codes
- 84156 - QTY (1)
- 83520 - QTY (2)
Includes
- Total Protein
- Free Urinary Kappa Light Chains
- Free Urinary Kappa Excretion/Day
- Free Urinary Lambda Light Chains
- Free Urinary Lambda Excretion/Day
Performing Laboratory
ARUP
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Urine, 24-hour (well-mixed) | Clean container | Refrigerate during collection. | Refrigerated | Transfer 1 mL aliquot from a well-mixed 24-hour collection into a standard aliquot tube. Record total volume and collection time interval on tube. |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Urine, random | Clean container | Refrigerated | Urine supernatant is also acceptable. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 0.5 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Refrigerated | 3 weeks |
| Frozen | 6 months |
| Ambient | Unacceptable |
Days Performed
Sun - Sat
Turnaround Time
2 - 4 days
Methodology
| Name | Description |
|---|---|
| Quantitative Immunoturbidimetric |
Special Info
Include total volume and collection time interval on transport tube and with order. This test is New York DOH approved.
Clinical Info
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. 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 urine 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.