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 alphathalassemia with confirmation by corresponding alphagenotyping studies. The RBC indices reduce as alphaglobin genes reduce in sickle cell trait (SCT) patients, which decreases the extent of intravascular 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 alphathalassemia in SCT patients thus, circumventing the much costlier alphagenotyping 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 sle 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 agargel 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 alphathalassemia and 338/933 were heterozygous alphathalassemia, based on trimodal distribution of HbS. Conclusion: Genotyping is costlier for majority of the poor nonaffording patients in Indian government setups, so this study is suitable to screen for associated alphathalassemia in SCT patients.