Thalassemia and Hemoglobinopathy Despite Normal Level of Hemoglobin Concentration and Normal Mean Corpuscular Volume

The small mean corpuscular volume (MCV) of red blood cell is one of the indicators for thalassemia and hemoglobinopathy screening. As other screening methods, it may have some degrees of limitation. The retrospective study was performed among 104 patients who had various kinds of thalassemia or hemoglobinopathy despite having normal hemoglobin (Hb) concentration and normal mean corpuscular volume (MCV). Every participant had MCV > 80 fL and Hb > 12 g% for females and Hb > 13 g% for males, using automated hematology analyzer. Without genotype study, 104 cases from 1,054 (9.9%) samples of Hb typing using the capillary zone electrophoresis fulfilled the inclusion criteria. There were Hb E trait of 92 (88.5%), Hb CS trait of 8 (7.7%), beta±thalassemia/Hb E of 2 (1.9%), double heterozygote of Hb E and CS of 1 (0.9%) and beta±thalassemia trait of 1 (0.9%). Their mean Hb concentration, MCV and MCH were 13.4 ± 1.2 g%, 84.7 ± 3.6 fL and 26.7 ± 1.7 pg respectively. Only 27.8% of them were shown to be positive for single tube osmotic fragility (OF) test. In the case of screening, the combination of the normal Hb concentration, the normal MCV and negative OF test do not preclude the chance of any people to harbor thalassemia or hemoglobinopathy particularly in the area with especially high prevalences of these mutations like Thailand.