Four-color flow cytometry shows strong concordance with bone marrow morphology and cytogenetics in the evaluation for myelodysplasia.

The ability of 4-color flow cytometry (FC) to help identify myelodysplastic syndromes (MDSs) was evaluated in 124 bone marrow aspirates from unselected patients with unexplained cytopenias and/or monocytosis. The morphologic features of bone marrow aspirate smears were correlated with FC and cytogenetic findings blindly, and patterns of antigen expression were compared with patterns seen in nonneoplastic and normal marrow specimens. Of 124 cases, 58 (46.7%) had definitive FC abnormalities ("flow-abnormal"), 19 cases (15.3%) had mild FC abnormalities of indeterminate significance, and 47 cases (37.9%) had essentially normal FC. Highly significant differences were identified between the flow-abnormal group and other groups in mean myeloid blast percentages and numbers of abnormal antigens expressed, even when the analysis was limited to cases with fewer than 5% myeloid blasts. Strikingly, flow-abnormal cases constituted 50 (89%) of the 56 morphologically abnormal cases and 31 (94%) of the 33 cytogenetically abnormal cases, demonstrating the strong concordance of FC-identified antigenic abnormalities with morphologic features and cytogenetics in the evaluation of patients with unexplained cytopenias.