Beta-Thalassaemia trait: haematological parameters

ABSTRACT

Beta-Thalassaemia syndromes are a group of hereditary disorders characterised by a genetic deficiency in the synthesis of beta-globin chains due to a defect in beta-globin genes. The objective of this study was to determine the haematological features of beta-thalassaemia trait [BTT], and to determine the sensitivity of Mean Corpuscular Volume [MCV], Mean Corpuscular Haemoglobin [MCH] and Mentzer Index [MI] as a screening tool for beta-thalassaemia trait. A descriptive study was conducted in Hayatabad Medical Complex, Peshawar from May 2009 to May 2010 with 203 subjects having BTT. Blood samples were collected in EDTA anti-coagulated tubes. RBC indices were taken as part of complete blood count [CBC] by haematology analyser, and Haemoglobin [Hb] electrophoresis was done to determine the HbA2 percentage. The data was collected and analyzed on statistical software for demographic details, RBC indices and HBA2 levels. Out of 203 patients, 92 [45%] were males and 111 [55%] were females. Most patients tested were in the 15-45 year age group. One-hundred-sixty [79%] patients had anaemia. MCV was lower than 76 fl in all the cases. Mean MCV was 59.1 fl. MCH was low, the mean MCH being 19.3 g/dl. MCH <26 gave sensitivity of 99% in detecting BTT. We calculated MI for these cases and found out that it was <12 in 75% of cases and <15 in 197 [97%]. beta-thalassaemia traits present with a microcytic hypochromic blood picture, detected on simple haematology analysers as low MCV and MCH and MI which provide a useful screening tool for beta- thalassaemia trait