Free Light Chains, Quantitative, Urine
Also known as: U FLC
Use
This test aids in the monitoring of patients with urinary monoclonal proteins, commonly referred to as Bence Jones protein. It is useful for assessing disease progression or response to therapy in cases where urine electrophoresis is not reliable for quantifying Bence Jones Protein. Interpretation of results should be done in conjunction with urine immunofixation, especially when high levels of urinary polyclonal free light chains are present without detectable Bence Jones protein by immunofixation. Furthermore, the test can help track patients' clinical status when used in a broader clinical and laboratory context.
Special Instructions
Ensure to collect a 24-hour urine sample, refrigerate during collection, and transfer a 1 mL aliquot to an ARUP Standard Transport Tube, with a minimum volume of 0.5 mL. Record total volume and collection time on the transport tube and test request form. The test is performed every day of the week with results reported within 1 to 3 days.
Limitations
The quantitative values of free light chains may not always align with clinical outcomes if there is significant polyclonal free light chain presence. Antigen excess is rare but possible, and can lead to misleading results. Discrepancies may occur if analyte excess is not detected. Proper correlation with immunofixation is essential for identifying inconsistent results. The total urinary protein value determined turbidimetrically using combined albumin and light chains may differ from total protein values determined chemically, as chemical methods often underestimate light chains in urine.
New York Approved
Methodology
Immunoassay (Quantitative Immunoturbidimetry)
Biomarkers
LOINC Codes
- 2889-4
- 38176-4
- 38177-2
- 38178-0
- 38169-9
- 19153-6
- 30211-7
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
1 mL
Minimum Volume
0.5 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Collect 24-hour urine and refrigerate during collection. Transfer 1 mL aliquot from a well-mixed 24-hour collection.
Storage Instructions
Refrigerated
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 3 weeks |
| Frozen | 6 months |