Change in Units for Kappa/Lambda Free Light Chains in Serum Test

Effective Tuesday, August 27, 2013, the units for “KAPPA-LAMBDA FREE LIGHT CHAIN RATIO, BLOOD” (Epic # LAB7454) will change from mg/dL to mg/L.  This increases the separate kappa and lambda concentrations each by factor of 10.  The kappa-lambda ratio does not change.

This will change reference ranges as follows:


Current reference range using mg/dL

New reference range using mg/L

Kappa free light chain

0.33 – 1.94 mg/dL

3.3 – 19.4 mg/L

Lambda free light chain

0.57 – 2.63 mg/dL

5.7 – 26.3 mg/L

Kappa/lambda ratio

0.26 – 1.65

0.26 – 1.65 [no change]

A comment will be appended as a footnote to all results related to this change in units and when the switch occurred.  The kappa and lambda concentrations in Epic Results Review will be offset from results prior to August 27, 2013, to provide visual clue that units have changed.

Questions should be directed to Matthew Krasowski, MD, PhD, medical director of the Clinical Chemistry Laboratory (384-9380,