Kappa/Lamba Light Chains, Free with Ratio, Serum : 11234

FLTCHN : 11234

Immunoglobulin Free Light Chains

This test includes Kappa Light Chain, Free,   Lambda Light Chain, Free, and  the  Kappa/Lambda  Light Chains, Free Ratio

Plain red top tube or Serum Separator Tube (SST).

Centrifuge the Serum Separator Tube (SST); if plain red top, centrifuge and aliquot serum (2.0 mL, minimum 1.0 mL) into a standard transport tube.

Room temperature.

Room temperature: 72 hours; Refrigerated: 21 days; Frozen: 30 days

Gross hemolysis, gross lipemia, microbial contamination, heavy visible particulate

Monday - Friday

1-4 days

Kappa Light Chain, Free, Serum                                      3.3-19.4 mg/L 
Lambda Light Chain, Free, Serum                                    5.7-26.3 mg/L 
Kappa/Lambda Light Chains Free with Ratio, Serum       0.26-1.65 

Immunoglobulin molecules consist of two identical heavy chains (alpha (α), delta (δ), epsilon (ε), gamma (γ), and mu (μ)) which define the immunoglobulin class and two identical light chains, kappa (κ) and lambda (λ). Each light chain is covalently linked to a heavy chain and the two heavy chains are linked covalently at the hinge region. In healthy individuals, the majority of light chain in serum exists in this form, bound to heavy chain. However, low levels of free light chain (FLC) are found in serum of normal individuals due to the over-production and secretion of FLC by the plasma cells. While the molecular weight of both light chains is ≈22.5kD, in serum κ free light chain (κ – FLC) exists predominantly as monomer and λ free light chain (λ- FLC) as a covalently linked dimer with a molecular weight of ≈45kD. This will lead to a differential glomerular filtration rate for κ – FLC and λ- FLC and may explain the observed ratio of κ – FLC to λ- FLC of 0.625 in serum compared to the ratio of bound κ to λ of 2.0. Elevated serum levels of monoclonal FLC are associated with malignant plasma cell proliferation (e.g., multiple myeloma), amyloid light chain (AL) amyloidosis and light chain deposition disease. Raised serum levels of polyclonal FLC may be associated with autoimmune diseases such as systemic lupus erythematosus.