- Serum monoclonal paraprotein (M-protein) level ≥5 g/L (0.5 g/dL); or urine M-protein level ≥200 mg/24 hours; or serum immunoglobulin free light chain ≥100 mg/L (10 mg/dL) and abnormal serum immunoglobulin kappa lambda free light chain ratio (See Appendix A)