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Test ID FLCP Immunoglobulin Free Light Chains, Serum

Useful For

Monitoring patients with monoclonal light chain diseases but no M-spike on protein electrophoresis

Profile Information

Test ID Reporting Name Available Separately Always Performed
KFLC Kappa Free Light Chain, S No Yes
LFLC Lambda Free Light Chain, S No Yes
KLR Kappa/Lambda FLC Ratio No Yes

Testing Algorithm

The following algorithms are available in Special Instructions:

-Laboratory Approach to the Diagnosis of Amyloidosis

-Laboratory Screening Tests for Suspected Multiple Myeloma

Method Name

Nephelometry

Reporting Name

Immunoglobulin Free Light Chains, S

Specimen Type

Serum

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 1 mL

Forms: If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

General Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)

Neurology Test Request Form-General (T732) (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)

Hematopathology/Cytogenetics Test Request Form (T726) (http://www.mayomedicallaboratories.com/it-mmfiles/hematopathology-request-form.pdf)

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 14 days
  Frozen  21 days
  Ambient  72 hours

Clinical Information

The monoclonal gammopathies are characterized by a clonal expansion of plasma cells that secrete a monoclonal immunoglobulin (Ig). The monoclonal Ig 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 multiple myeloma (LCMM), Waldenstrom macroglobulinemia (WM), nonsecretory myeloma (NSMM), smoldering multiple myeloma (SMM), monoclonal gammopathy of undetermined significance (MGUS), primary systemic amyloidosis (AL), and light chain deposition disease (LCDD).

 

Monoclonal proteins are typically detected by serum protein electrophoresis (SPEP) and immunofixation (IF). However, 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 SPEP.

 

A sensitive nephelometric assay specific for kappa free light chain (FLC) and lambda free light chain (FLC) that doesn't recognize light chains bound to Ig heavy chains has recently been described. This automated, nephelometric assay is reported to be more sensitive than IF for detection of monoclonal FLC. In some patients with NSMM, AL, or LCDD the FLC assay provides a positive identification of a monoclonal serum light chain when the serum IF is negative. In addition, the quantitation of FLC has been correlated with disease activity in patients with NSMM and AL.

 

See Laboratory Approach to the Diagnosis of Amyloidosis and Laboratory Screening Tests for Suspected Multiple Myeloma in Special Instructions.

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

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.

 

Moderate-to-marked lipemia may interfere with the ability to perform testing.

Day(s) Performed

Monday through Saturday; Continuously until 3 p.m.

Report Available

Same day/1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test has been cleared or approved by the U.S. 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

83883 x 2

NY State Approved

Yes