| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Immunoglobulin Free Light Chains, Serum
MessageThe following algorithms are available:
-Amyloidosis: Laboratory Approach to Diagnosis
-Multiple Myeloma: Laboratory Screenin
-Amyloidosis: Laboratory Approach to Diagnosis
-Multiple Myeloma: Laboratory Screenin
Test Code
FLCS
Alias/See Also
Epic: LAB735
Mayo: FLCS
Mayo: FLCS
CPT Codes
83521 x 2
Includes
| 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:
-Amyloidosis: Laboratory Approach to Diagnosis
-Multiple Myeloma: Laboratory Screening
-Amyloidosis: Laboratory Approach to Diagnosis
-Multiple Myeloma: Laboratory Screening
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 1 mL
Minimum Volume
0.5 mL
Other Acceptable Specimens
Collection Container: Red top
Instructions
Centrifuge and aliquot serum into a plastic vial.
Transport Container
Plastic vial
Specimen Stability
Room temperature: 72 hours
Refrigerated: 28 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross lipemia
Methodology
Turbidimetry
Setup Schedule
Monday through Friday
Report Available
Same day/1 to 2 days
Limitations
CAUTIONS
Elevated kappa and lambda (K/L) free light chain (FLC) may occur due to polyclonal hypergammaglobulinemia or impaired renal clearance. A specific increase in FLC (eg, FLC K:L ratio) must be demonstrated for diagnostic purposes.
This assay has not been established for use with the pediatric population.
Moderate-to-marked lipemia may interfere with the ability to perform testing.
Elevated kappa and lambda (K/L) free light chain (FLC) may occur due to polyclonal hypergammaglobulinemia or impaired renal clearance. A specific increase in FLC (eg, FLC K:L ratio) must be demonstrated for diagnostic purposes.
This assay has not been established for use with the pediatric population.
Moderate-to-marked lipemia may interfere with the ability to perform testing.
Reference Range
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
0.33-1.94 mg/dL
LAMBDA-FREE LIGHT CHAIN
0.57-2.63 mg/dL
KAPPA/LAMBDA FLC RATIO
0.26-1.65
INTERPRETATION
The specificity of this assay for detection of monoclonal light chains relies on the ratio of free kappa and lambda (K/L) light chains. Once an abnormal free light chain (FLC) K/L ratio has been demonstrated and a diagnosis has been made, the quantitation of the monoclonal light chain is useful for monitoring disease activity.
Changes in FLC quantitation reflect changes in the size of the monoclonal plasma cell population. Our experience to date is limited, but changes of more than 25% or trending of multiple specimens are needed to conclude biological significance.
Changes in FLC quantitation reflect changes in the size of the monoclonal plasma cell population. Our experience to date is limited, but changes of more than 25% or trending of multiple specimens are needed to conclude biological significance.
Clinical Significance
USEFUL 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
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
CLINICAL INFORMATION
The monoclonal gammopathies are characterized by a clonal expansion of plasma cells that secrete a monoclonal immunoglobulin. The monoclonal immunoglobulin secreted by these cells serves as a marker of the clonal proliferation, and the quantitation of monoclonal protein can be used to monitor the disease course. The monoclonal gammopathies include multiple myeloma (MM), light chain MM (LCMM), Waldenstrom macroglobulinemia (WM), nonsecretory MM (NSMM), smoldering MM (SMM), monoclonal gammopathy of undetermined significance (MGUS), primary systemic amyloidosis (AL), and light chain deposition disease (LCDD). The monoclonal light chain diseases (LCMM, AL, LCDD, and NSMM) often do not have serum monoclonal proteins in high enough concentration to be detected and quantitated by serum protein electrophoresis.
An elevated ratio of kappa to lambda free light chains (FLC K/L) indicates a monoclonal kappa FLC, and an abnormally low FLC K/L indicates a monoclonal lambda FLC. The kappa and lambda FLC may both be elevated in the sera of patients with polyclonal hypergammaglobulinemia, but the FLC K/L is normal. If a patient has an abnormal serum FLC K/L ratio but has no serum monoclonal protein detected by immunofixation, a urine monoclonal protein study (eg, immunofixation) should be performed and the serum immunofixation should be repeated.
The FLC K/L ratio may be useful as a diagnostic test for patients in whom immunofixation for serum monoclonal light chains is negative and in whom there is a suspicion of primary systemic amyloidosis, light chain deposition disease, or non-secretory myeloma.
The quantitation of kappa or lambda immunoglobulin free light chains may be used to monitor disease activity in patients with monoclonal light chain diseases without a serum M-spike.
An elevated ratio of kappa to lambda free light chains (FLC K/L) indicates a monoclonal kappa FLC, and an abnormally low FLC K/L indicates a monoclonal lambda FLC. The kappa and lambda FLC may both be elevated in the sera of patients with polyclonal hypergammaglobulinemia, but the FLC K/L is normal. If a patient has an abnormal serum FLC K/L ratio but has no serum monoclonal protein detected by immunofixation, a urine monoclonal protein study (eg, immunofixation) should be performed and the serum immunofixation should be repeated.
The FLC K/L ratio may be useful as a diagnostic test for patients in whom immunofixation for serum monoclonal light chains is negative and in whom there is a suspicion of primary systemic amyloidosis, light chain deposition disease, or non-secretory myeloma.
The quantitation of kappa or lambda immunoglobulin free light chains may be used to monitor disease activity in patients with monoclonal light chain diseases without a serum M-spike.
Performing Laboratory
Mayo Clinic Laboratories - Rochester
3050 Superior Drive NW
Rochester, MN 55901
Additional Information
Immunoglobulin Free Light Chains, Serum
Last Updated: June 19, 2023
Last Review: N. Wolford, June 19, 2023