Bessman等人根据MCV和红细胞体积分布宽度(RDW)提出了一个新的贫血分类法。RDW表示红细胞大小分布的不均一性,相当于末梢血片中观察到的红细胞大小不等的异质性指标,可鉴别红细胞同质性贫血和异质性贫血。小红细胞增多症患者,任何时候的MCV都将反映过去四个月中生成的所有红细胞MCV的总和, Bessman et al. Proposed a new anemia classification based on the MCV and the red blood cell volume distribution width (RDW). RDW indicates heterogeneity of red blood cell size distribution, which is equivalent to the heterogeneity of erythrocyte size observed in peripheral blood cells, and can identify erythrocyte homogeneity anemia and heterogeneous anemia. In patients with polycythaemia, the MCV at any time will reflect the sum of all red cell MCVs produced in the past four months,