Laboratory screening of monoclonal gammopathies: incidence of serum monoclonal immunoglobulins during a five years survey in a general hospital.

During a five years survey of unselected serum protein electrophoreses in a general hospital, 2347 sera (0.95%) were found to be positive for one or more monoclonal immunoglobulins. Class and type distribution of monoclonal immunoglobulins (characterized by means of immunofixation electrophoresis) mostly corresponded with the literature data. Nevertheless, higher incidence and lower mean age at detection were observed for IgG monoclonal components. This finding is probably related to the discovery of a large number of micro-monoclonal immunoglobulins with no association with B-lymphoproliferative disorders, mostly belonging to the IgG class and affecting younger people. The need is stressed for a widespread standardization of the techniques employed for detection and characterization of monoclonal immunoglobulins, in order to obtain more comparable results.