Thalassemia Carriers among Healthy Blood Donors

Abstract

Thalassemia is a common hereditary anaemia in Southeast Asia which may also be found among healthy blood donors. The established screening method is less sensitive and can miss donors with clinically silent Thalassemia. The Thalassemia screening tests may help in selection of truly healthy blood donors, hence providing the most functional red cell concentrates for blood transfusion. This is an extension study from our previous work, aiming to detect thalassemia trait among clinically asymptomatic blood donors. We performed Thalassemia screening in 738 healthy blood donors who were allowed for blood donation using full blood count and haemoglobin (Hb) analysis. After screening analyses using high performance liquid chromatography, capillary zone electrophoresis and agarose gel electrophoresis, 85 samples were excluded from the study due to inadequate volume for DNA analysis. Five hundred twelve (512/653; 78.4%) samples were within normal limit and 74 (74/653; 11.3%) samples with Hb less than 12.5 g/dl. Thirty eight donors were found to have Thalassemia and/or haemoglobinopathies by Hb analysis. The remaining 105 blood donors samples with value of MCV less than 80 fl and/or MCH lower than 27 pg with no detectable abnormal pattern from Hb analysis subjected to multiplex PCR that was capable of detecting deletional and nondeletional of the α-globin gene. Majority (79/653; 2.1%) of them had no identified mutation while 23 (23/653; 3.5%) of them had heterozygous α-3.7 deletion, 2 (2/653; 0.3%) had heterozygous α--SEA deletion and only one (1/653; 0.1%) had heterozygous α-4.2 deletion. This data indicates that 74 (74/653; 11.3%) of our blood donors were anaemic, 64 (64/65; 39.8%) had haemoglobinopathies and 79 (79/653; 12.1%) were presumptively had iron deficiency anaemia based on red blood cell indices. Provision of best quality pack red cells should be selected for patients who require regular blood transfusion in order to maintain appropriate Hb level.