[Multiple myeloma immunophenotyping: method validation].

Flow cytometric immunophenotyping has become essential for management of multiple myeloma (assessment of clonality, prognostic information on the risk of progression in gammopathy of undetermined significance, minimal residual disease monitoring). Immunophenotyping of bone marrow plasma cells is routinely used in the haematology laboratory of the University Hospital of Toulouse. To guarantee the reliability of this technique, the laboratory decided to check this method in compliance with the NF ISO EN 15189, standard for medical laboratories requirements. As expected, the method showed good technical performances. However, this initiative has demonstrated the importance of the sample quality and of the control of the preanalytical and analytical conditions. This process led us to maximize our professional pratices.