The study is aimed to evaluate of serum imunoglobulin free light chain levels measurement in multiple myeloma and their relationship to each stage not only of traditional Durie – Salmon staging system, but also to recently established International Staging System and South West Oncology Group staging system. The results of analysis showed that serum free light chain levels corelate with each stage of staging systems based on dynamic indices (serum albumin and ß2-microglobulin) more expressively, than traditional Durie –Salmon staging system. The study also confirmed dependency of serum free light chain levels upon renal function.

        Key words: imunoglobulin free light chains, multiple myeloma, staging systems