Lastly, the FLC assay is useful for monitoring disease activity in patients with NSMM, LCMM, AL, and LCDD in whom there is no measurable M-spike on serum or urine protein electrophoresis.
1] Nonstandard abbreviations: FLC, free light chain; NSMM, nonsecretory multiple myeloma; AL, primary systemic amyloidosis; LCDD, light chain deposition disease; LCMM, light chain multiple myeloma; IFE, immunofixation electrophoresis; PCD, plasma cell disorder; MCUS, monoclonal gammopathy of undetermined significance; and SMM, smoldering multiple myeloma.
From this registry, 28 patients with LCMM were selected for this analysis.
Of the 28 LCMM patients in the study, 9 were positive for [kappa] light chain and 19 for [lambda] light chain.
Results for sequential serum FLCs and 24-h urinary monoclonal protein were compared for a representative [kappa] and a representative [lambda] LCMM patient (Fig.
This correlation suggests that serum measurements may provide a logical and feasible alternative to 24-h urine collections in monitoring patients with LCMM.