Phenotypic and allelic profile of ABO and Rhésus D blood group system among blood donor in Antananarivo.

This study assessed the phenotypic and allelic profiles of ABO and Rhesus D blood group system among first time blood donors at the National Centre of Blood Supply of Antananarivo. We collected through this retrospective study all data registered during 7 years of practice (from 2003 to 2009). Age and sex were analysed with the result of ABO and RhD screening. They were tested both with Beth Vincent and Simonin tests which were performed in a plate, by using commercial monoclonal antibody (Diaclone(®) et Eryclone(®)), and home-made red cells tests. The Rh D was performed with the same commercial kits. The frequencies of alleles were calculated by using Bernstein method. Data about 45,857 donors were obtained. A male predominance (80.46%) was found and most of our donors were aged <40 (74.92%). 98.90% of the donors were Rh D positive. Phenotypic distribution of each ABO antigen was, respectively, 22.61, 29.66, 6.13 and 41.60% for A, B, AB and O antigen. Allelic frequencies of A, B and O were 0.1559, 0.1987 and 0.6454. These results confirmed the fact that Madagascan population had admixed ethnic origin.