Detection of circulating myeloma cells (CMCs) by flow cytometry. CMCs are detected by gating for a population of CD38⁺/CD45^- cells. Healthy individuals do not have any cells in the CD38⁺/CD45^- gate (A). Panels B and C represent patients with a few (5) or many (1080) CMCs, respectively. Each analysis evaluates 50 000 events.