DOI: 10.1373/clinchem.2011.163766


A 71-year-old woman with a 9-year history of monoclonal gammopathy of undetermined significance presented with anemia [hemoglobin, 11.6 g/dL (116 g/L); reference interval (RI),3 12–15.5 g/dL (120–155 g/L)], an increased serum calcium concentration [10.2 mg/dL (2.55 mmol/L); RI, 8.9–10.1 mg/dL (2.22–2.52 mmol/L)], and a 4800-mg/dL (48-g/L) monoclonal protein band (M-spike) after serum protein electrophoresis (SPEP). Immunofixation electrophoresis (IFE) revealed a monoclonal IgA κ protein. Her IgA concentration was markedly increased to 4720 mg/dL [47.2 g/L; RI, 61–356 mg/dL (0.61–3.56 g/L)], and the serum immunoglobulin free light chain (FLC) κ/λ ratio was 7 (RI, 0.26–1.65).