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Kappa and Lambda Free light Chains, serum

Item Value
Approval req'd? No
Available Stat? No
Test code FKL
Test group light chains
Performed by Immunology
In House Availability Tuesday, Thursday (day shift)
Method Turbidimetry
Collection Instructions Avoid hemolysis
Container type Gold top (Red top acceptable)
Amount to Collect 1 mL blood
Sample type Serum
Preferred volume 0.5 mL serum
Min. Volume 0.3 mL serum
UCSF Rejection Criteria Hemolysis, lipemia
Processing notes Refrigerate sample
Units mg/L
Normal range
Kappa light chains 3.3-19.4 mg/L
Lambda light chains 5.7-26.3 mg/L
Kappa/Lambda ratio 0.26-1.65
Synonyms K/L; kappa/lambda
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 occurrence of lambda light chains as dimers whose serum 1/2-life is approximately 3 times longer than 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 urine protein electrophoresis along with immunofixation electrophoresis 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, macroglobulinemia, Mu heavy chain disease, primary amyloidosis, light chain deposition disease, monoclonal gammopathies, and some cases of 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). In each of these cases the kappa/lambda ratio still remains within normal limits.
CPT coding 83883 x2
LOINC code 40844-3
Last Updated 5/1/2011 4:09:51 PM
Entry Number 1106
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