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Free Light Chains

Alternative Names:Light Chains Free
Laboratory:Clinical Biochemistry
Test Code:FLC
Specimen Types:Serum
Container Types:
SST
Collection & Request Instructions:

Useful for the diagnosis and subsequent monitoring of non-secretory myeloma, light chain deposition disease and primary amyloidosis where serum and urine protein electrophoresis are negative.

Transport Instructions between Sites and/or Laboratories:Room Temperature
Additional Notes:

Reference Intervals:
Free Kappa:                  3.3—19.4 mg/L
Free lambda:                5.71—26.3 mg/L
Kappa/Lambda ratio:  0.26—1.65

(In patients with renal failure, with no evidence of monoclonal proteins, a ratio of 0.37–3.1* can be used.)

*Hutchison C.A, et al. Serum free light chain measurement aids the diagnosis of myeloma in patients with severe renal failure. BMC Nephrology 2008; 9:11 doi: 10.1186/1471-2369-9-11

 

Elevated free kappa and/or lambda accompanied by a normal kappa/lambda ratio can be due to polyclonal activation or renal failure and should be interpreted with caution.

Long term studies of patients with MGUS and smoldering myeloma have shown a high biological variability of free light chain levels (CV 27.8%) in patients with stable disease (Katzmann et al. Clin Chem 2011: 1687-1692). Clinicians should take this into account when interpreting free light  chain levels in their patients.

Method: Binding Site SPAPLUS (Turbidimetry) from 1/6/11.