RRs = (Cpre- Cpost-corr)/ Cpre x 100 (1) where Cpre is the predialysis solute level, and Cpost-corr is the post-dialysis solute concentration. The values measured during dialysis were corrected for hemoconcentration due to the patient's weight loss assuming a unicompartmental behavior of light chains described by the following formula: Cpost-corr = Cpost/ {1+ [DeltaBW/(0.2xBWpost)]} (2) where Cpost-corr is the post-dialysis solute concentration and Cpost-corr is the concentration of light chains corrected for the hemoconcentration, Delta body weight (DeltaBW) is the weight subtracted during dialysis, and BW (body weight) is the body weight at the end of dialysis.