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Kappa and Lambda Free light Chains, serum
|Test group||light chains|
|In House Availability||Tuesday, Thursday (day shift)|
|Collection Instructions||Avoid hemolysis|
|Container type||Gold top (Red top acceptable)|
|Amount to Collect||1 mL blood|
|Preferred volume||0.5 mL serum|
|Min. Volume||0.3 mL serum|
|UCSF Rejection Criteria||Hemolysis, lipemia|
|Processing notes||Refrigerate sample|
|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|
|Last Updated||5/1/2011 4:09:51 PM|