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Kappa/Lambda Free Light Chains w/ Ratio

Item Value
Approval req'd? No
Available Stat? No
Test code KALAM
Performed by? Chemistry
Sendout? No
Price range $
In House Availability Twice a week
Method Turbidimetry
Container type gold top gel tube (plain red top acceptable)
Amount to Collect 4 mL whole blood
Collection Instructions Avoid hemolysis.
Sample type Serum
Preferred volume 2 mL serum
Min. Volume 0.5 mL serum
Special instructions Refrigerate sample.
Units mg/dL
Normal range
Kappa light chains 0.33-1.94 mg/dL
Lambda light chains 0.57-2.63 mg/dL
Kappa/Lambda ratio 0.26-1.65

Synonyms K/L; kappa/lambda; kappa/lambda ratio; serum light chain ratio
Stability 3 weeks @ refrigerated temperatures
Turn around times 1-5 days
Additional information In serum, the kappa/lambda ratio of whole immunoglobulin molecules is 2:1, whereas the kappa/lambda ratio of free light chains is 1:1.5. The latter is attributed to the occurence of lambda light chains as dimers whose serum half-life is approximately 3 times longer that that of monomeric kappa light chains. Excess production of kappa or lambda light chains alters the kappa/lambda ratio. Alterations that fall outside the normal range may be attributable to the presence of monoclonal light chains. Serum or protein electrophoresis along with immunoelectrophoresis should be performed to confirm the presence of a monoclonal paraprotein.

Measurement of free light chain concentration in serum can be useful for diagnosis, prognosis, monitoring disease activity, and following response to therapy of many disorders, including plasma cell myeloma, macroglobinemia, Mu heavy chain disease, primary amyloidosis, light chain deposition disease, monoclonal gammopathies, and certain lymphoproliferative disorders with paraprotein production, such as chronic lymphocytic leukemia.

Chronic infections, chronic inflammatory diseases, and renal insufficiency may be accompanied by a diffuse increase in both kappa and lambda free light chains. Additionally, the serum concentration of free light chains increases with age (particularly over age 60). However, in each of these cases, the kappa/lambda ratio remains within normal limits.
CPT coding 83883 x2
Last Updated 1/14/2011 11:25:43 AM
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