Significance of 801 monoclonal proteins detected during 7 years of screening in a district general hospital.

This study describes the biochemical follow-up of 801 patients in whom a monoclonal protein had been detected, by screening protein electrophoresis, during a 7-year period. A further blood sample was obtained from 61% of the group and information was available on an additional 32%. Follow-up times ranged from 2 months to almost 8 years. The level of monoclonal protein was measured and any increase related to the level at detection, presence of reduced polyclonal immunoglobulins (RPI), and Bence Jones Protein (BJP). Seventeen (2.1%) monoclonal proteins had disappeared and 428 (88%) demonstrated no significant change in level. Only 26 (3.2%) patients showed a significant increase. This suggests that the majority of monoclonal proteins detected on screening electrophoresis are benign. The presence of BJP is still considered to be the most significant biochemical prognostic criterion. In contrast, finding RPI seems to be least useful. A monoclonal protein level greater than 19 g/l is usually associated with an immunocyte related disease as is an increase in the level of more than 6 g/l. Therefore, assessment of the benign or malignant nature of monoclonal proteins using biochemical prognostic criteria at detection alone is not sufficient. It is recommended that the minimum follow-up should involve review at 3 months and then at yearly intervals.