Multiparameter flow cytometry quantification of bone marrow plasma cells at diagnosis provides more prognostic information than morphological assessment in myeloma patients

Quantification of bone marrow plasma cells in multiple myeloma patients using conventional morphology is of limited prognostic value, while the merit of multiparameter flow cytometry immunophenotyping is still considered unproven. Here we compare the bone marrow plasma cell counts obtained by morphology and multiparameter flow cytometry and explore the potential prognostic impact of both techniques in 765 newly diagnosed, uniformly treated multiple myeloma patients. Although multiparameter flow cytometry generally yields lower plasma cell counts (median percentage of 11% vs. 40%, respectively; p