CD79A and plasmacytoma: Therefore, stage I myeloma contains all of the following criteria: hemoglobin > 10 g/dL, normal level of serum calcium, normal bone structure or solitary plasmacytoma only, and low M-component (IgG < 5 g/dL, IgA < 3 g/dL, urine light chains < 4 g/24 h) [12, 13].