- Measurable levels of monoclonal protein (M protein): > 1 g/dL of IgG or IgM M-protein or > 0.5 g/dL IgA or IgD M protein on serum protein electrophoresis OR > 200 mg of free light chain on a 24 hour urine protein electrophoresis which must be obtained within 4 weeks prior to registration OR > 20 mg/dL involved free light chain on serum free light chain testing with an abnormal kappa:lambda light chain ratio. Note that if both serum and urine m-components are present, both must be followed in order to evaluate response. Both SPEP and UPEP must be performed within 28 days prior to registration.