Screening Algorithms for Monoclonal Gammopathies

Abstract

In this issue of Clinical Chemistry , Piehler et al. (1) present data on the use of serum protein electrophoresis (SPE),1 clinical history, and selective use of serum immunoglobulin free light chain (FLC) assay as a diagnostic screening algorithm for multiple myeloma (MM) in a general hospital population and conclude that this algorithm allows for efficient diagnosis or exclusion of multiple myeloma. The authors investigated clinical histories and sera of the 3818 samples sent to their laboratory for SPE over a 1-year period. These samples translated into 2854 unique patients: 2302 who did not have either an abnormality detected on SPE or a clinical history that included unexplained anemia, renal disease, hypercalcemia, increased sedimentation rate, and/or osteolysis, bone pain, or fractures; and 545 who met at least 1 of these criteria. Of the 545, 157 were excluded because their monoclonal protein had been previously recognized, leaving 332 patients: 83 who had a newly identified monoclonal band on SPE and 249 who had no monoclonal band detected. These 332 patients were subsequently screened with the FLC assay. Of the group without a monoclonal protein detected by SPE, 56 patients had an abnormal FLC ratio, and only 14% of these had a plasma cell disorder. Using this methodology, the authors “missed” only 4 diagnoses—2 myelomas and 2 plasmacytomas—and conclude that their algorithm detected 95% of all cases of MM, Waldenstrom macroglobulinemia, or primary amyloidosis. The authors should be congratulated on this endeavor, but there are 2 major limitations of their study that must be addressed. The first is that clinical …