Evaluation of the Impact of Renal Failure on Correlation and Concordance Between 2 Free Light Chain Assays

摘要

Measurement of serum free light chains (FLCs) is recommended for diagnosis of monoclonal gammopathies. FLC measurements with Freelite (Binding Site) and N Latex FLC (Siemens) assays were performed on 1215 fresh sera samples from patients with or without monoclonal gammopathy and renal failure. A good correlation was demonstrated between both assays, but it remained 7.6% to 20.8% discordances between the methods related to the FLC ratio interpretation. In patient follow-up, few discrepancies were observed. Neither of the assays performed better than the other: they provide comparable but not equivalent results, and discrepancies are not linked to renal failure stage. Interpretation must take into account clinical data and the same assay must be used for patient follow-up.