Comparing Five Diagnostic Criteria for Multiple Myeloma: A Retrospective Study of 227 Cases

Aims and Background Several diagnostic criteria for multiple myeloma are used in clinical practice, and it can be difficult to reach a diagnosis when a patient's clinical presentation is consistent with one criterion but not with another. However, no study to date has compared the superiority of the different diagnostic criteria. The aim of this research is to compare the efficacy of five diagnostic criteria for multiple myeloma and to find the reasons for misdiagnosis of atypical multiple myeloma cases. Methods and Study Design A total of 227 multiple myeloma cases were retrospectively studied. The clinical data (including plasma cell morphology, flow cytometry, immunofixation electrophoresis, imaging information and clinical manifestations) were scrutinized and the reasons underlying the misdiagnoses analyzed. Results The Traditional Domestic criteria had the highest misdiagnosis rate due to the high fixed bone marrow plasma cell percentage and serum M-protein thresholds. The WHO criteria and the International Myeloma Working Group 2009 criteria exhibited relatively low misdiagnosis rates due to their lower bone marrow plasma cell percentage thresholds, flexible criteria and detailed end-organ damage descriptions. The 2003 International Myeloma Working Group criteria and the 2011 Chinese Myeloma Working Group criteria exhibited perfect performance, as each focused on monoclonal plasma cell proliferation and not on fixed bone marrow plasma cell percentage and serum M-protein thresholds. Conclusions The 2003 International Myeloma Working Group criteria and the 2011 Chinese Myeloma Working Group criteria have advantages in diagnosing early or atypical multiple myeloma cases. To avoid misdiagnosing some atypical cases of multiple myeloma, attention should be paid to evidence of monoclonal plasma cell proliferation, and flow cytometry may be a useful tool for discovering monoclonal plasma cell proliferation. Advanced imaging techniques should be used to confirm any suspected or atypical findings on metastatic bone survey.