330 A. ROVÓ ET AL. ERYTHROGRAM PATTERN OF SIDEROBLASTIC CHANGES provide a visual representation of RBC characteristics, based on the volume and hemoglobin concentration. These erythrograms show a characteristic pattern in diverse conditions such as iron deﬁciency, thalassemia, autoimmune hemolytic anemia and spherocytosis, and their use is valuable in daily practice (Ricerca et al., 1987; Pati, Patton & Harris, 1989; Macdougall et al., 1992; d’Onofrio et al., 1992; Robertson et al., 1992; McKay et al., 1993; Kutter et al., 2002). We observed a characteristic erythrogram in patients with sideroblastic anemia, consisting of an unusual broad scatter distribution of the red cells in respect of their volume and hemoglobin concentra- tion, with a substantial number of dots overlapping onto the hypochromic and the microcytic quadrants. This erythrogram is clearly distinctive from iron deﬁciency, megaloblastic anemia or MDS without RS (Figure 1). We sought to conﬁrm the diagnostic value (a) (ii) (b) (i) (c) (d) (e) (f) Figure 1. The erythrogram is a graphical representation of red blood cells (RBCs) produced by the automated cell analyzer ADVIA 120 (Bayer), based on cell by cell measurements of hemoglobin concentration (abscissa), and red cell volume (ordinate). (a) Diagram of an erythrogram divided into nine areas, according to the red cell volume and hemoglobin concentration. Normally the erythrocytes are located within the area 1 (normochromic, normocytic RBC). RBCs located on the left side of the ﬁrst vertical line passing at 280 g/l are hypochromic. RBCs located on the right side of the second vertical line passing at 410 g/l are hyperchromic. RBCs located above the ﬁrst horizontal line passing at 120 fL are macrocytic; RBCs located below the second horizontal line, assigned at 60 fL are microcytic. The erythrogram offers a sensitive and speciﬁc method for detection of minority of RBC populations, and provides a typical pattern which assists in differentiating between diseases such as iron deﬁciency anemia, thalassemia minor, and macrocytosis. (b) Patient with sideroblastic anemia: (bi) Iron staining of the bone marrow cytology with RS. (bii) Erythrogram of peripheral blood from the same patient showing a typical RS-pattern, with the RBCs largely scattered over eight of nine areas (all except area seven). In comparison erythrograms with different pattern: (c) normal erythrogram, (d) iron deﬁciency anemia; the RBCs are mainly moved to area four, with microcytic, hypochromic RBCs, (e) thalassemia minor; the RBCs are moved mainly to area six with microcytic, normochromic RBCs, and (f) macrocytosis; the RBCs are mainly moved to area ﬁve, with macrocytic, normochromic RBCs. 2009 The Authors Journal compilation 2009 Blackwell Publishing Ltd, Int. Jnl. Lab. Hem. 2010, 32, 329–335