Multiple Myeloma Proteins: Evaluation of Laboratory Methods as AIDS for Diagnosis

Twenty-four clinically confirmed multiple myeloma patients (20 IgG and 4 IgA classes) were evaluated by six laboratory methods. The detection rates of paraproteins were: 55% of patients positive for Bence-Jones proteins in urine; 63% suggestive by electrophoresis; 50% positive by immuno-electrophoresis; 54% suggestive by Laurell's two-dimensional immunoelectrophoresis; 50% suggestive by single radial immuno-diffusion; and 88% positive by micro-double immuno-diffusion technique. Micro-double immuno-diffusion had advantages over other procedures for increasing the detection rate of para-proteins from 88% to 100% by using specific antisera for heavy and light chains. Routine immunoglobulin assays by micro-double immuno-diffusion technique manifested 22 additional patients with paraproteins, alerting clinicians to potential multiple myeloma diagnosis.