Method comparison and clinical classification agreement between Freelite and N-Latex serum-free light chain assays for clinical laboratory implementation
In 33 paired residual sera, Freelite produced significantly higher free-kappa values than N-Latex, while lambda did not differ significantly. Correlations were strong (rho 0.897 and 0.951), but Passing-Bablok analysis showed proportional kappa bias and Bland-Altman limits widened at extreme concentrations. Using assay-specific reference intervals, kappa/lambda classification agreed in 30 of 33 samples (91%; kappa 0.79). Numerical results are therefore not directly interchangeable.
Thai researchersDararat Dankai · Phichayut Phinyo · Wiyada Dankai