39-year-old man who on a routine physical exam was found to have elevated serum creatine at 1.4 mg/dL associated with elevated serum free kappa to lambda ratio at 27. The serum protein electrophoresis (SPEP) test was negative for paraprotein. Urine protein electrophoresis (UPEP) showed a free kappa light chain. Bone marrow biopsy was done and showed 1-2% kappa restricted plasma cells. Additional workup revealed a 24-hour urine protein of 0.5 g, negative fat pad biopsy for amyloid, and negative skeletal survey. A kidney biopsy was performed.

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	Sam Albadri, M.B., Ch.B., M.S. Fellow, Renal Pathology Mayo Clinic @sam_albadri
	Samih Nasr, M.D. Consultant, Anatomic Pathology Mayo Clinic Professor of Laboratory Medicine and Pathology Mayo Clinic College of Medicine and Science