Which Protein Bands Are Significant?

The serum protein electrophoresis pattern (SPEP)2 for an 82-year-old female patient with known monoclonal gammopathy of undetermined significance demonstrated 2 aberrant protein bands, one in the α2-β1 interzone (Fig. 1A, fat arrow) and one in the β1-β2 interzone (Fig. 1A, thin arrow). The immunofixation electrophoresis (IFE) (Fig. 1B) revealed a large IgA κ paraprotein in the β1-β2 interzone (Fig. 1B, thin arrow) …