SERUM AND URINARY FLC QUANTIFICATION COMPARED BY IMMUNOASSAY AND ELECTROPHORESIS

1. SERUM AND URINARY FLC QUANTIFICATION COMPARED BY IMMUNOASSAY AND ELECTROPHORESIS Sophie Claeyssens 1 , F. Le Roy 2 , V. Brunel 1 , M. Quillard 1 , M. Godin 2 , A. Lavoinne 1 1 - Medical Biochemistry, Rouen University Hospital, Rouen, France 2 - Nephrology, Rouen University Hospital, Rouen, France 2011 Biochimie Biochemistry Poster 8

2. 1 – Introduction : In mutiple myeloma (MM) free light chains (FLC) are involved in the pathogenesis of renal failure, a major cause of morbi-mortality. Since reversibility of renal failure often can be achieved at time of diagnosis, early quantification of FLC contributes to appropriately prevent and manage renal failure. In this study, we have compared for the first time, the quantification of FLC by immunonephelometry and by electrophoresis in serum and in urine of the patients with MM at presentation or at relapse from remission. 2011 Biochimie Biochemistry Poster 8

4. 2 b - Methods b) immunonephelometry (Freelite®, The Binding Site) on Siemens Healthcare Diagnostics BNII Analyser.  FLC expressed as total, K + L, concentration in serum and as total, K + L, 24h urinary excretion. Statistical Data : The intra-class correlation coefficient (ICC), the Bland-Altman analysis and the Spearman's rank correlation coefficient were performed . 2011 Biochimie Biochemistry Poster 8

5. 3 a - Results  in serum and in urine , FLC values were up to 9 - and 11-fold higher , respectively, by immunonephelometry than by electrophoresis  urinary FLC values measured by immunonephelometry were up to 7-fold higher than total proteinuria values. 2011 Biochimie Biochemistry Poster 8

6. 3 b – Results Figure : Bland-Altman plots presenting comparison of serum and urinary free light chains quantification by immunonephelometry and electrophoresis 2011 Biochimie Biochemistry Poster 8

7. 3 b – Results Comparison of immunonephelometry and electrophoresi s for the quantification , in serum and in urine : - of FLC indicated poor reproducibility and poor agreement - of albumin indicated good reproducibility and good agreement 2011 Biochimie Biochemistry Poster 8