Several disorders are associated with a monoclonal immunoglobulin detected
by serum or urine electrophoresis, the most common being a monoclonal gammo
pathy of undetermined significance, multiple myeloma, Waldenstrom's macrogl
obulinemia, and amyloidosis. The clinical features of these conditions, as
well as other similar entities, are described in this review. The objective
is to demonstrate the importance of electrophoretic studies in the differe
ntial diagnosis of plasma cell dyscrasias and in guiding the decision for r
ational therapies.