- Measurable monoclonal protein in the serum (for immunoglobin [Ig]G or IgM, >= 1.0 g/dL using serum protein electrophoresis [SPEP]/immunofixation electrophoresis [IFE]; for IgA, an SPEP/IFE confirming the presence of a monoclonal IgA band plus a quantitative IgA level of >= 750 mg/dL) OR measurable urine Bence Jones paraprotein (>= 500mg/24hrs) OR a measurable serum free light chain (FLC), defined as an involved FLC level of >10 mg/dl, and a serum FLC ratio that is abnormal