Introduction: The aim of thalassaemia screening is to reduce thalassaemia syndromes with significant clinical implication. Therefore, detection of α0 thalassaemia with two genes deletion is clinically more important than α+ thalassaemia with one gene deletion. The aim of this study is to determine the mean corpuscular haemoglobin (MCH) cut-off point for α0 thalassaemia screening. Method: A total of 688 α0 and α+ thalassaemia cases confirmed by DNA analysis were analysed. Red cell indices (MCV, MCH, RBC, Hb) were retrieved from the laboratory information system. Receiver operating characteristic (ROC) curve is generated to determine the MCH cut-off point for α0 thalassaemia. The diagnostic performance of MCH cut-off value was evaluated with a validation group comprising 100 samples of alpha thalassaemia carriers. Results: ROC curve analysis with area under the curve (AUC) of 0.969 showed that MCH at cut-off of 23.5pg has high sensitivity and specificity in detecting α0 thalassaemia with 98% sensitivity and 85% specificity. Conclusion: MCH cut-off value of 23.5pg can be adopted as the cut-off point for α0 thalassaemia screening to detect clinically significant thalassaemia syndrome and reduce cost and burden of screening.
Haemoglobin E (Hb E) is a variant of structurally abnormal haemoglobin that can be found very commonly in the Asian countries particularly the Southeast Asian [1]. [H1] Alpha thalassaemia is a red cell disorder which is caused by deletion or mutation of one or more of the four alpha globin genes leading to absence or decrease in production of alpha globin peptides [2]. This disorder is far more common in South East Asian regions and in Malaysia itself, and the gene frequency is about 4.1% [2]. The interactions of Hb E and alpha thalassaemia are evident in Kelantan which is bordered by southern Thailand. Using capillary electrophoresis (CE), a reduction of Hb E level is noticed as compared to Hb E heterozygotes. DNA analysis should be done to determine the presence of concurrent alpha thalassaemia variant. This study was done to evaluate haematological parameters using automated blood counters, morphology of red cells, Hb separation and quantitation of Hb fractions using CE and molecular analysis for alpha thalassemia. The study also aimed to discover cut off point of Hb E level in heterozygous Hb E patients with concurrent deletional alpha thalassaemia by CE.