The thalassemias result from defective globin chain production. Most of these abnormal Hb do not have clinical symptoms however, some of these mutations may change the functional properties or stability of the Hb and lead to a clinical disorder. These structural Hb variants are commonly caused by single amino acid substitutions in the α or β globin chains. Hemoglobinopathies may be roughly divided into two groups, the structural hemoglobin (Hb) variants (abnormal Hb) and the thalassemias. All service labs highly recommend to select the technique(s) they are most familiar and most economic one for their routine use. The major limitation for using NGS in the screening of thalassemia is its cost which is still expensive. This technique gives an accurate diagnosis of thalassemia that may be misdiagnosed by other conventional techniques. Recently, screening for both α- and β-thalassemia genes by next-generation sequencing (NGS) has been introduced. All of these techniques have some advantages and disadvantages. Various molecular techniques have been used for point mutation detection in β-thalassemia and large-deletion detection in α-thalassemia. Only DNA analysis can be made for specific thalassemia mutation diagnosis. However, those are presumptive diagnoses. Thalassemia genotypes can be characterized by the intensities between alpha-/beta-globin chains or alpha-/beta-mRNA ratios. In case of α-thalassemia gene interaction, it can affect the amount of Hb A2/E. Both systems have a good correlation, but the interpretation under the CE system should be done with caution because Hb A2 is clearly separated from Hb E. These two systems give both qualitative and quantitative analysis of Hb components and help to do thalassemia prenatal and postnatal diagnoses within a short period. Today, Hb analysis may be carried out by either automatic high-performance liquid chromatography (HPLC) or capillary zone electrophoresis (CE) system. However, these two red blood cell indices cannot discriminate between thalassemia trait and iron deficiency or between α- and β-thalassemic conditions. Thalassemic red blood cell analysis with an automated hematology analyzer is a primary screening for thalassemia since microcytosis and decreased Hb content of red blood cells are hallmarks of all thalassemic red blood cells. Laboratory diagnosis of thalassemia requires a number of tests including red blood cell indices and Hb and DNA analyses. These abnormal globin genes in different combinations lead to many thalassemic diseases including three severe thalassemia diseases, i.e., homozygous β-thalassemia, β-thalassemia/Hb E, and Hb Bart’s hydrops fetalis. 2Guangxi Key Laboratory of Thalassemia Research, Guangxi Medical University, Nanning, ChinaĪlpha- and β-thalassemias and abnormal hemoglobin (Hb) are common in tropical countries.1Thalassemia Research Center, Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.Thongperm Munkongdee 1 Ping Chen 2 Pranee Winichagoon 1 Suthat Fucharoen 1 Kittiphong Paiboonsukwong 1*
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