The plasma cell population is identified in 3 separate gating steps using forward scatter (FSC)/side scatter (SSC), the CD45/CD38, and the CD38/CD138 gate. Subsequently, clonality of the plasma cell population is identified by using antibodies to kappa and lambda. The left lower histogram shows binding of diamino-2-phenylindole (DAPI) to the DNA in kappa monoclonal plasma cells. Based on nuclear content, a significant fraction of plasma cells is in S-phase, reflective of proliferative activity.