[Show abstract][Hide abstract] ABSTRACT: The standardization of biochemical measurement procedures in multiple myeloma is necessary for reliable prognostic stratification of patients in multicentric trials. The new prognostic index International Staging System for multiple myeloma uses only two laboratory markers, albumin and beta-2 microglobulin. Our study compared results of albumin, beta-2 microglobulin and monoclonal immunoglobulin measurements from six centers which provide treatment for multiple myeloma in the Czech Republic and attempted to standardize the analytic procedures. We have found that the measurement of albumin is well standardized and the results from all laboratories were comparable. The measurement of beta-2 microglobulin achieved comparability only after a partial unification of analytical methods. The determination of monoclonal immunoglobulin concentration provided comparable results for concentrations higher than 20 g/l with higher variability for lower values.