Testing of the pre-transfusional blood phenotype, which has been carried out at the Regional Blood Bank in Uberaba since 1996, is an important procedure to improve safety of blood transfusions. This study aims to describe the frequency of irregular red blood cell antibodies in multiple-transfused patients from 1997 to 2005. In a retrospective study, data from all alloimmunized patients were collected from the blood bank files. Descriptive statistical analysis was performed and a comparison of proportions was made using the Z test. Alloimmunization was observed in 173 (0.75%) of the 23,220 transfused patients, with an average of 5.7 transfusions per patient. The frequency of the Rh and Kell systems jointly was over 70%. The proportion of anti-D was significantly higher in women (p<0.05) and no difference was noted in the Rh system between Caucasians and non-Caucasians. Seventy percent (70%) of the patients were over 30 years of age. Out of the 73 patients with registered diseases, 39.73% had acute anemias, 31.51% chronic anemias and 28.77% oncological or onco-hematologic diseases. Approximately 70% of antibodies were discovered before the 10th transfusion. The low frequency of alloimmunization observed at the Regional Blood Bank of Uberaba reinforces the importance of pre-transfusional blood phenotype screening for all multiple-transfused patients as well as its adoption as a common practice in all hemotherapy center.
Alloimmunization; irregular antibodies; multitransfused patients
