Characterize the species of protein or proteins in cases of proteinuria. Techniques can identify albumin, γ-globulin, γ-globulin fragments (light chains, Bence Jones proteins); of value in the study of monoclonal gammopathies, lymphoproliferative diseases, including lymphoma; special application to multiple myeloma, macroglobulinemia of Waldenström, and amyloidosis; work up monoclonal gammopathy (M-spike).