Test Code FLCS Immunoglobulin Free Light Chains, Serum
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Secondary ID
608250Useful For
Monitoring serum from patients with monoclonal light chain diseases without a M-spike on protein electrophoresis
May be useful as a diagnostic test in patients in whom there is a suspicion of primary systemic amyloidosis, light chain deposition disease, or non-secretory myeloma
Profile Information
Test ID | Reporting Name | Available Separately | Always Performed |
---|---|---|---|
KFLCS | Kappa Free Light Chain, S | No | Yes |
LFLCS | Lambda Free Light Chain, S | No | Yes |
KLRS | Kappa/Lambda FLC Ratio | No | Yes |
Testing Algorithm
The following algorithms are available:
Special Instructions
Method Name
Turbidimetry
Reporting Name
Immunoglobulin Free Light Chains, SSpecimen Type
SerumSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 28 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Reject Due To
Gross hemolysis | OK |
Gross lipemia | Reject |
Gross icterus | OK |
Reference Values
KAPPA-FREE LIGHT CHAIN
0.33-1.94 mg/dL
LAMBDA-FREE LIGHT CHAIN
0.57-2.63 mg/dL
KAPPA/LAMBDA FLC RATIO
0.26-1.65
Clinical Reference
1. Kaleta E, Kyle R, Clark R, Katzmann J: Analysis of patients with gamma-heavy chain disease by the heavy/light chain and free light chain assays. Clin Chem Lab Med. 2014 May;52(5):665-669. doi: 10.1515/cclm-2013-0714
2. Palladini G, Russo P, Bosoni T, et al: Identification of amyloidogenic light chains requires the combination of serum-free light chain assay with immunofixation of serum and urine. Clin Chem. 2009 Mar;55(3):499-504. doi: 10.1373/clinchem.2008.117143
3. Dispenzieri A, Kyle R, Merlini G, et al: International Myeloma Working Group guidelines for serum-free light chain analysis in multiple myeloma and related disorders. Leukemia. 2009 Feb;23(2):215-224. doi: 10.1038/leu.2008.307
4. Drayson M, Tang LX, Drew R, Mead GP, Carr-Smith H, Bradwell AR: Serum free light chain measurements for identifying and monitoring patients with nonsecretory multiple myeloma. Blood. 2001 May 1;97(9):2900-2902
Method Description
The determination of the soluble antigen concentration by turbidimetric methods involves the reaction with specific antiserum to form insoluble complexes. When light is passed through the suspension formed a portion of the light is transmitted and focused onto a photodiode by an optical lens system. The amount of transmitted light is indirectly proportional to the specific protein concentration in the test sample. Concentrations are automatically calculated by reference to a calibrations curve stored within the instrument.(Package inserts: Optilite Freelite Kappa Free Kit. The Binding Site Group, Ltd; 08/2018; Optilite Freelite Lambda Free Kit. The Binding Site Group, Ltd; 08/2018)
Performing Laboratory

Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
83521 x 2
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
FLCS | Immunoglobulin Free Light Chains, S | In Process |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
LFLCS | Lambda Free Light Chain, S | 33944-0 |
KLRS | Kappa/Lambda FLC Ratio | 48378-4 |
KFLCS | Kappa Free Light Chain, S | 36916-5 |
Day(s) Performed
Monday through Friday
Report Available
Same day/1 to 2 daysForms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:
General Request (T239)