can trimodal distribution of hbs levels in sickle cell traits be used to predict the associated alpha-thalassemia for screening cases in central india?

background: until now, trimodal distribution of hbs has been seen by six different studies in the world when associated with alpha-thalassemia with confirmation by corresponding alpha-genotyping studies. the rbc indices reduce as alpha-globin genes reduce in sickle cell trait (sct) patients, which decreases the extent of intra-vascular sickling and thus betters the clinical course of the patients. this is a pioneer study conducted on central indian poor population to use the already proven six studies to screen associated alpha-thalassemia in sct patients thus, circumventing the much costlier alpha-genotyping studies. moreover, it aimed to study the haematological parameters in such cases. methods: the study was performed at rhdmc, iggmc, nagpur, india from 2003 to 2012. the sample population was suspected cases of haemolytic anaemia. cbc and rbc indices were obtained by a cell analyzer. the sickle solubility test positively screened cases were confirmed by agar-gel haemoglobin electrophoresis at ph 8.6. finally, quantitative assessment of haemoglobin variants was performed by hplc. results: out of total 5819 cases over ten years, 933 cases were sickle heterozygotes. overall, 180/933 subjects were predicted to be homozygous alpha-thalassemia and 338/933 were heterozygous alpha-thalassemia, based on trimodal distribution of hbs. conclusion: genotyping is costlier for majority of the poor non-affording patients in indian government set-ups, so this study is suitable to screen for associated alpha-thalassemia in sct patients.