The diagnosis of myelodysplastic syndromes (MDS) is based upon cytopenias, morphologic dysplasia, and cytogenetic abnormalities. Because morphologic dyspoiesis may be subtle, and many cases have normal cytogenetics, additional objective diagnostic tools are needed. We previously developed a novel peripheral blood neutrophil flow-cytometric (FCM) scoring system to identify patients with MDS. Here, in an analysis of 25 patients, we demonstrate that FCM abnormalities are independent of currently measured parameters in MDS, including cytopenias, marrow blast percent, and IPSS score. Importantly, FCM abnormalities were seen in 9/16 MDS patients with normal cytogenetics, suggesting that this simple, non-invasive assay could play a central role in the diagnosis of MDS.