334 A. ROVÓ ET AL. ERYTHROGRAM PATTERN OF SIDEROBLASTIC CHANGES this validation, we conﬁrm that the peripheral blood erythrogram is highly predictive of RS in the bone marrow. Siderotic granulations within the mitochondria form the hallmark of RS. Aspirate smears represent the gold standard for assessing RS. Mitochondrial iron is dissolved during treatment with chelation and decalciﬁcation agents. Therefore, RS remain unstained in parafﬁn sections obtained by decalciﬁed tissue. They can only be identiﬁed in undecalciﬁed material of plastic sections or with the use of special staining techniques (Tham & Cousar, 1993). Thus, in patients with ﬁbrosis and dry tap in marrow aspiration, side- roblastic changes can be easily missed when no special attention is brought. According to our results, even in patients with dry tap, we can assume the presence of sideroblastic changes when patients have a typical RS-pattern. Moreover, if erythroblasts are present in peripheral blood, an iron staining could support this assumption by detecting circulating RS. We demonstrated here the value of the erythro- gram as a simple diagnostic tool in the routine labo- ratory analysis. It works as a ‘ﬁngerprint’ and can evoke a diagnosis at ‘ﬁrst look’ and consequently drive the investigations to conﬁrm our suspicion. Despite that, a size distribution histogram allows identifying dimorphic red blood cell populations, a two dimensional erythrogram has a great speciﬁcity for suspecting sideroblastic changes. As sideroblastic anemia is frequently a normocytic, normochromic anemia, it can be easily misinterpreted with anemia of chronic disorder. Nine of 21 patients from the valida- tion group presented normocytic and normochromic anemia without neutropenia and thrombocytopenia. In these patients, the erythrogram (RS-pattern) was a strong argument to think about an underlying myeloid neoplasms and to perform a bone marrow investigation. As for iron deﬁciency, thalassemia or macrocytosis, the erythrogram pattern has also a great visual impact to detect sideroblastic changes. Additionally, the RS-pattern is supported by the com- bination of the following RBC-indices: normal MCV and MCHC, RDW 19%, hypoRBC 3% and normal CHr. In conclusion, this is the ﬁrst study evaluating sys- tematically the value of the erythrogram of peripheral blood as a diagnostic tool in daily practice to predict sideroblastic changes in the bone marrow. These results conﬁrm the great value of the erythrogram as part of the routine evaluation of peripheral blood count. A C K N O W L E D G E M E N T S We thank ‘Automaten and Morphologie-Team’ of the Hematology Laboratory of Basel University Hospital, and Christine Danis for all their contributions to this work. We also thank Mariana Gimpelewicz for the English language corrections. A U T H O R C O N T R I B U T I O N S A. Rov o´ designed the study, did morphological inter- pretation of bone marrows, searched for cases, and wrote the manuscript. G. St u¨ssi did morphological interpretation of bone marrows, searched for cases, and reviewed the manuscript. S. Meyer-Monard, G. Favre, D. Tsakiris, D. Heim, J. Halter, C. Arber, J. Passweg and A. Gratwohl did morphological interpretation of bone marrows, and reviewed the manuscript. A. Tichelli designed the study, did mor- phological interpretation of bone marrows, searched for cases, and reviewed the manuscript. R E F E R E N C E S Fishbane S., Galgano C., Langley R.C., Jr, Canﬁeld W. & Maesaka J.K. (1997) Reticulocyte hemoglobin content in the evaluation of iron status of hemodialy- sis patients. Kidney International 52, 217–222. Fishbane S., Shapiro W., Dutka P., Valenzuela O.F. & Faubert J. (2001) A randomized trial of iron deﬁciency test- ing strategies in hemodialysis patients. Kidney International 60, 2406–2411. Kotisaari S., Romppanen J., Penttila I. & Punnonen K. (2002) The Advia 120 red blood cells and reticulocyte indices are useful in diagnosis of iron-deﬁciency anemia. European Journal of Haematol- ogy 68, 150–156. Kutter D., Coulon N., Stirn F., Thoma M. & Janecki J. (2002) Demonstration and quantiﬁcation of ‘‘hyperchromic’’ ery- throcytes by haematological analysers. Application to screening for hereditary Journal compilation 2009 The Authors 2009 Blackwell Publishing Ltd, Int. Jnl. Lab. Hem. 2010, 32, 329–335