Comparison of Bromcresol Purple and Capillary Protein Electrophoresis for Quantification of Serum Albumin in Multiple Myeloma

Abstract

According to the International Staging System (1), serum albumin concentration is a key factor in determining patient prognosis in multiple myeloma. A recent study published in Clinical Chemistry described significant discordance between bromcresol green (BCG)1 albumin dye and agarose gel serum protein electrophoresis (SPEP) for albumin concentration determination in patients with high concentrations of monoclonal (M)- protein (2). Also available, however, are commonly used alternative methods for albumin determination, such as bromcresol purple (BCP) albumin dye and capillary zone SPEP (3). To examine whether the previously observed comparative discordance of measured albumin concentration is limited only to the BCG dye and agarose gel SPEP methods of albumin determination (2), we retrospectively compared measured albumin concentrations as determined by BCP albumin dye and capillary zone SPEP in a large cohort of multiple myeloma patients. The ratio of measured BCP albumin to SPEP albumin concentrations in patients with a previously identified monoclonal protein was retrospectively calculated for 579 specimens submitted to the University of Arkansas Immunology laboratory for routine serum protein electrophoresis by capillary zone SPEP. All specimens had concurrent albumin determination by a BCP albumin dye method. These consisted of 355 IgG, 122 IgA, 29 IgM, 13 IgD, and 60 free-light-chain myeloma patient specimens. …