Suspicious bands in serum and urine protein immunofixation electrophoresis tests in patients with and without a history of monoclonal gammopathies: a retrospective database study

None of the patients initially reported as having an SfMB developed monoclonal gammopathy during their follow-up period. We recommend that cases reported as "suspicious" be managed separately in patients with and without a prior monoclonal gammopathy diagnosis, where the term "weak positive" may be more appropriate in patients with a known monoclonal gammopathy.