Role of flow cytometry of peripheral blood and bone marrow aspirates in early myeloma.

Flow cytometric immunophenotyping (FCM) of multiple myeloma (MM) is commonly accepted in academic centers as providing clinically significant information and is becoming increasingly utilized in the private setting. FCM has established clinical relevance in the following: (1) differential diagnosis of MM from other plasma cell dyscrasias; (2) differentiating MM from lymphoplasmacytic lymphoma (LPL) and other non-Hodgkin lymphomas; (3) diagnosis of unusual cases of myeloma (eg, to confirm the diagnosis of rare cases of IgM MM); (4) determining the risk of progression of monoclonal gammopathy of uncertain significance (MGUS) and smoldering MM; (5) prognostication in MM; and (6) minimal residual disease detection (MRD) post therapy. FCM may have an emerging role in the enumeration of abnormal plasma cells in diagnosis of MM, but further studies are needed. We review the clinical value of FCM in evaluation of peripheral blood and bone marrow in early myeloma.