Blood group distribution in an urban population of patient targeted blood donors

Abstract

Background: The frequencies of ABO and Rhesus D blood groups vary from one population to another.

Objective: To determine the frequencies of the ABO and Rhesus D blood groups and to assess the preparedness of the hospital based patient targeted blood donor unit in the provision of blood and blood products and also to determine the blood groups of patients attending the antenatal clinic over the same period.

Design: A retrospective study using data from the hospital's blood transfusion unit.

Setting: The Aga Khan Hospital, Nairobi.

Subjects: All persons donating blood and attending the antenatal clinic between October 1997 and December 1997 were included in the study.

Results: Blood group O was found to be most frequent: 49% in indigenous African donors and ANC attendants, 45% in the general donor population and 34% among Asian donors. The frequency of blood group B was 33% in the Asian donors, 27% in all donors, 25% in African donors, and 24% in ANC attendants. Group AB was seven per cent in Asian donors, five per cent in both the general donor population and the ANC attendants and four per cent in the African donors. The frequency of blood group A was 26% in Asian donors, 23% in all donors and 22% in both the African donors and ANC attendants. Ninety four per cent of the indigenous African donors were Rhesus D positive, 97% of the ANC attendants were Rhesus D positive and 90% of the Asian donors were Rhesus D positive.

Conclusion: The blood groups of blood and blood products available at the hospital based transfusion unit closely correlate with those of the general population. A positive bias towards the rarer blood groups AB and Rh D negative is noted. The Rhesus D antigen has a high prevalence in indigenous Africans.