Test Directory

Clear All
Test Code
SFLCP
Test Name
Light Chains, Free, Profile
CPT Codes
83521 X 2
Included Tests
  • Kappa Free Light Chains
  • Lambda Free Light Chains
  • Kappa/Lambda Free Light Chains Ratio
Expected Turnaround Time
3 - 7 days
Clinical Utility
Quantitative serum free light chain evaluation provides higher sensitivity and precision than standard serum protein electrophoresis (SPEP) assays for the detection and monitoring of patients with multiple myeloma, especially those with early-stage disease, non-secretory myeloma, light chain myeloma, or systemic primary amyloidosis. It is a superior method of assessing treatment response, disease remission, and disease stage in these patients. Normal concentrations of serum free light chains are several orders of magnitude lower than serum light chains bound to immunoglobulin, and normal renal function serves to prevent loss of small proteins in urine. While most myeloma patients have significant levels of detectable free light chains in serum, only about half of myeloma patients excrete free light chains in urine. As urine protein levels vary with kidney function, serum free light chain levels more accurately reflect tumor burden or stage in myeloma patients.
Specimen and Container Info

Preferred Specimen Type: Serum

Desired Specimen Volume: 2 mL

Preferred Collection Container: Gold Top, Serum Separator
Processing and Submission Instructions

Separator tubes: Contains clot activator and gel for separating serum from cells, but not anticoagulant. Separate serum from cells as soon as the clot has formed (30 minutes). If specimen is centrifuged before clotting is complete, a fibrin clot will form on top of the cell. This may cause the gel barrier to not be intact and could cause improper separation of serum and cells, possibly affecting test results.
Transport Instructions

Transport refrigerated. 
Stability Requirements

Refrigerated

7 days

Frozen

<20°C for long-term storage. 

Freeze/Thaw Cycles

Avoid multiple freeze/thaw cycles. 
Methodology
Turbidimetric
Reference Intervals

Kappa Free Light Chains:

3.30 - 19.40 mg/L

Lambda Free Light Chains:

5.70 - 26.30 mg/L

Kappa/Lambda Ratio:

0.26 - 1.65

 
Performing Location
Roble Road Core Laboratory
Testing Schedule
Routine, 5 times per week
The American Medical Association (AMA) Current Procedural Terminology (CPT) codes published by HNL Lab Medicine are guidelines and are intended for informational purposes only. CPT coding is the exclusive responsibility of the billing entity. View the Terms.
© 2026 HNL Lab Medicine. All rights reserved.