THE PREVALENCE AND SIGNIFICANCE OF RED CELL ALLOANTIBODIES IN BLOOD DONORS AND RECIPIENTS IN A TERTIARY HOSPITAL IN NIGERIA

Abstract

Blood transfusion is one of the vital supporting therapies in the management of patients and all efforts must be geared towards ensuring greater blood safety. Currently, screening for red cell alloantibodies is not done routinely for blood donors and patients at the University College Hospital, Ibadan. There are studies on the prevalence of red cell alloantibodies in sickle cell anaemia patients. However, there is no study on other groups of Nigerian patients that are frequently transfused, along with the donor population from whom the transfused blood units are derived.

Objectives The aim of this study is to determine the prevalence and identity of red cell alloantibodies in blood donors and patients at the University College Hospital, Ibadan with a view to improving blood safety and transfusion support for patients, including those who in the future may require organ and stem cell transplantation when these programs are fully developed. The study would assess the feasibility of the adoption of the “type and screen” policy and abbreviated crossmatch.

Material and Methods The study population consisted of 1195 subjects, of which 725 were blood donors and 470 patients (587 samples). The patients were derived from Obstetrics and Gynaecology, Surgery, Medicine, Paediatrics and Haematology. A consecutive sampling technique was used for donor and patient selection. Data was collected with the aid of a questionnaire. Four millilitres of blood was collected in plain universal bottles and analysed for transfusion transmissible infections using ELISA, ABO and RhD blood grouping using microplate technique, red cell antibody screening and antibody identification (when required) using DiaMed gel technology. Approval was obtained from the UI/UCH Ethics Committee prior to commencement of the study.

Results The number of samples analysed for blood donors was 792, out of which 67 (8.5%) were positive for one or more TTIs. False negative results were found in 2.3% HIV, 2.7% HBV, 2.5% HCV and 0.2% had multiple TTIs. Seventeen (2.3%) of the blood donors had a previous history of blood transfusion. Of the 100 female donors, 53 (53%) of them had been
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pregnant in the past and only one (1%) had red cell alloantibodies. The prevalence of red cell alloantibodies in blood donors was 1.7%. There was no significant difference between the presence of red cell alloantibodies with those who had never been pregnant or transfused versus those who had been pregnant and/or transfused.

The prevalence of red cell alloantibodies in the patients was 5.6%. There was no statistical difference in the prevalence of red cell alloantibodies between the patient groups, Obstetric and Gynaecology, Surgery, Medicine, Paediatric and Haematology. There was also no correlation between prior transfusions received, parous versus nulliparous patients and the development of red cell alloantibodies. There was an association in the detection of alloantibodies in patients who had received anti-D prophylaxis (p<0.001).

Conclusion There was a higher prevalence of red cell alloantibodies in patients compared to the blood donor population. There is a statistically significant chance of detection of red cell alloantibodies after anti-D immune prophylaxis. Prior blood transfusions or pregnancies were not shown to play a significant role in the prevalence of red cell alloantibodies in our blood donor population. This study also underscores the risk of relying only on rapid screen tests in blood transfusion services.