Letters to Editor By electrophoresis at alkaline pH, 45.1% (378) of the samples showed a normal Hb migration pattern (Hb AA) and 7.76% (65) were characterized as Hb AS. After this preliminary analysis, the samples initially considered Hb AS were submitted to additional testing by high performance liquid chromatography (HPLC) and 16.92% (11) were characterized as variants that co-eluted with Hb S (Hb S-like). The data obtained in the chromatographic analysis, such as retention time (RT), percentage of Hb variant and the characteristic peaks were analyzed using the Library Variants software version 1.0 (Bio-Rad Laboratories) that characterizes some variants (Figure 1). All variants found were confirmed by molecular tests (PCR-RFLP).(4-6) In addition, we found two unidentified rare Hb variants; chromatographic analysis identified the first with a fraction of 23.8% and RT 4.61 minutes and the second with a variant fraction of 6.8% and RT of 4.56 minutes, both with alpha globin chain mutations. These samples require family studies and subsequent DNA sequencing for better characterization. The diagnosis of hemoglobinopathies based only on methods such as electrophoresis at alkaline pH in groups such as the Brazilian population formed after intense migration, incurs 17% of mistaken identity. We emphasize that this is the method of choice for most clinical laboratories because of its low cost and ease of handling. In recent years HPLC has proved to be reliable in the characterization of these variants. Furthermore, it is an automated and easy-to-use xxx and thus has been shown to support the main alternative in the diagnosis of hemoglobinopathies, allowing more accurate results and appropriate guidance.(6) References 1. Zamaro PJ, Bonini-Domingos CR. Hemoglobinas variantes - Contribuição para o estudo dos defeitos moleculares da hemoglobina humana na população brasileira. São Jose do Rio Preto (SP): Editora HN; 2010. 78 p. 2. Bonini-Domingos CR. Metodologias laboratoriais para o diagnóstico de hemoglobinopatias e talassemias. São José do Rio Preto (SP): Editora HN; 2006. 121 p. 3. Bonini-Domingos CR, Ondei LS, Zamaro PJ. Hemoglobinas similares a S no Brasil - um guia prático de identificação. São José do Rio Preto (SP): Editora HN; 2006. 59 p. 4. Srinivas U, Pati HP, Saxena R. Hemoglobin D-Punjab syndromes in India: a single center experience on cation-exchange high performance liquid chromatography. Hematology. 2010;15(3):178-81. 5. Chinelato-Fernandes AR, Mendiburu CF, Bonini-Domingos CR. Utilization of different methodologies for the characterization of Hb Hasharon heterozygotes. Genet Mol Res. 2006;5(1):1-6. 6. Joutovsky A, Hadzi-Nesic J, Nardi MA. HPLC retention time as a diagnostic tool for hemoglobin variants and hemoglobinopathies: a study of 60000 samples in a clinical diagnostic laboratory. Clin Chem. 2004;50(10):1736-47. Comment in: Clin Chem. 2005;51 (7):1303-4; author reply 1305. Rev Bras Hematol Hemoter. 2012;34(2):168-71 171