Letter to Editor (14.5%). These differences may be explained by the different types of equipment on the market today where the cell measurement methods may be different. Regarding erythrogram and leukogram parameters, the values found for both women and men did not show significant differences compared to values reported in the literature.(1,2,8) Reference values, stratified by gender, are described in Table 1. An important factor to be noted is the characteristic of the population involved in the current study. The Municipal Laboratory receives blood samples from about 100 government healthcare clinics scattered around the city of Curitiba that attend the city's most needy populations. Therefore, our results must be analyzed cautiously to avoid erroneous comparisons. I n s u m m a r y, o u r r e s u l t s s h o w e d t h a t d e s p i t e t h e improved technology of cell counting and analysis, the hematological parameters of the adult population of the city of Curitiba suffered no major changes compared to studies performed in the 1980s. However, our work incorporates one new parameter (red cell distribution width), and provides values that better reflect the current conditions of the majority of the adult population of the city of Curitiba, thereby allowing greater accuracy in the interpretation of the data provided by the complete blood count. xxx References 1. Hashimoto Y, Leonart MSS, Granato ES. Valores normais para o hemograma em adultos residentes em Curitiba. Trib Farm. (Curitiba). 1981;49-50(1-2):80-2. 2. Malvezzi M. Valores eritrocitários normais em população adulta de Curitiba após exclusão dos indivíduos deficientes de ferro [dissertation]. Curitiba: Faculdade de Medicina da UFPR; 1983. 3. Lewis SM, Bain BJ, Bates I. Hematologia Prática de Dacie Lewis. 9th ed. Porto Alegre: Artmed; 2006. 4. National Council for Clinical Laboratory Standards. How to define and determine reference intervals in the clinical laboratory; approved guideline. 2nd ed. Wayne, PA: NCCLS; Approved Guidelines C28-A2, v. 20, n. 13; 2000. 5. Tetrault GA. Laboratory statistics. In: Harry JB. Diagnóstico clínico e gestão por métodos laboratoriais. 20th ed. Philadelphia: Saunders; 2000. p. 138-47. 6. Failace R, Pranke P. Avaliação dos critérios de liberação direta dos resultados de hemogramas através de contadores eletrônicos. Rev Bras Hematol Hemoter. 2004;26(3):159-66. 7. Bain JB. Células sangüíneas: um guia prático. 3rd ed. Porto Alegre: Artmed, 2004. 8. Malvezzi M, Pasquini R. Valores de leucócitos em população adulta de Curitiba. Bol Soc Bras Hematol Hemoter. 1987;9:83-9. Reticulocytes indices in β thalassemia trait individuals Sandrine Comparsi Wagner1 Allyne Cristina Grando2 Simone Martins de Castro3 1Instituto de Ciências da Saúde, Universidade Feevale, Novo Hamburgo, RS, Brazil 2Universidade Feevale, Novo Hamburgo, RS, Brazil 3Analysis Clinical Department, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul – UFRGS, Porto Alegre, RS, Brazil Conflict-of-interest disclosure: The authors declare no competing financial interest Submitted: 4/20/2011 Accepted: 6/21/2011 Corresponding author: Sandrine Comparsi Wagner Universidade Feevale RS 239, 2755 93352-000 – Novo Hamburgo, RS, Brazil Phone: 55 51 3586-8800 sandrine@feevale.br www.rbhh.org or www.scielo.br/rbhh DOI: 10.5581/1516-8484.20110107 396 The thalassemias are a diverse group of microcytic and hemolytic anemias that are characterized by defective synthesis of one of the globin chains of adult hemoglobin. The β-thalassemias are characterized by a reduced (β+-thalassemia) or an absence (β0-thalassemia) of β globin synthesis which leads to imbalanced globin chain production.(1,2) This imbalanced synthesis results in a variable degree of anemia which stimulates erythropoietin production, leading to proliferation and expansion of the bone marrow. The β-thalassemias have a considerable phenotypic variation depending on multiple factors, which include the nature of the mutation involved. This leads to a wide range of presentations from profound anemia (requiring lifelong blood transfusions – β-thalassemia major) to extremely mild anemia (β-thalassemia trait).(2) Reticulocytes are juvenile red blood cells; they contain remnants of the ribosomal ribonucleic acid which is present in large amounts in the cytoplasm of the nucleated precursors from which they are derived. The number of reticulocytes in the peripheral blood is a fairly accurate reflection of erythropoietic activity assuming that reticulocytes are released from the bone marrow after the 'normal' time, and that they remain in circulation for the 'normal' period of time.(3) A total of 152 unrelated adults were included in this study: thirty with the ß- thalassemia trait diagnosed by high-performance liquid chromatography (HPLC-Variant, Bio- Rad, Milan, Italy)(4) with sequencing of the HBB gene using the primers described by Kimura(5) and Miranda(6) and 122 individuals recruited during their routine blood counts at the Pharmacy School Laboratory of the Universidade Federal do Rio Grande do Sul. The Ethics Committee of Hospital de Clínicas de Porto Alegre, Rio Grande do Sul approved the study protocol. Peripheral blood was collected using EDTA as anticoagulant. Hematological and reticulocyte data were obtained in an automated cell counter - Sysmex SE9500 (Sysmex, Kobe, Japan). Table 1 shows the hematological indices for β-thalassemic trait and control individuals. Individuals with the β-thalassemic trait presented with significantly higher levels (p-value < 0.05) of the following variables compared to controls: reticulocytes (percentage and number), medium fluorescence reticulocytes, high fluorescence reticulocytes and immature reticulocyte fraction. These results are in agreement with those reported by Noronha & Grotto with the exception of the immature reticulocyte fraction, where no Rev Bras Hematol Hemoter. 2011;33(5):393-7