Kappa-Lambda Quant Free Light Chain Ratio, Blood

Label Mnemonic:	KLFQT
Epic code:	LAB7454
Downtime form:	Doctor/Provider Orders - Pathology Core and Specialty Care Nursery

Chemistry
6240 RCP
356-3527

Specimen(s):

Blood

Collection Medium:

Pink top tube 6 mL (K2-EDTA)

Minimum:

Preferred Minimum: 3 mL whole blood

Rejection Criteria:

Plasma separator tube

Testing Schedule:

24 hrs/day, 7 days a week, including holidays.

Turn Around Time:

1 hour (upon receipt in laboratory)

Reference Range:

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

Comments:

Elevated absolute concentrations of both kappa and lambda (K/L) free light chains as well as K/L ratio may occur due to decreased renal function (see reference below) or polyclonal hypergammaglobulinemia. Results should be interpreted in conjunction with clinical history, physical examination, and other diagnostic data. This assay is highly sensitive to increasing concentrations of monoclonal free kappa or free lambda light chains in the serum of patients with evolving or relapsing myelomas.

References:

Long TE et al. Defining new reference intervals for serum free light chains in individuals with chronic kidney disease: Results of the iStopMM study. Blood Cancer Journal 12(9): 133, 2022. doi: 10.1038/s41408-022-00732-3.

Methodology:

Turbidimetric

CPT Code:

83521 x2