RESUMO
BACKGROUND: According to increased availability and awareness of automated blood bank analyzer with its speed and efficiency, use of automated analyzer in hospital blood bank has been increasing rapidly. We compared the ABO blood group typing results between automated analyzer IH-500 and manual method in healthy adults and patients with ABO discrepancies to provide useful information on interpretation of blood grouping results by automated analyzer. METHODS: Among healthy adults who underwent medical examinations, 400 samples (each 100 samples of A, B, O and AB type) were selected and evaluated the results and grades of blood grouping by automated and manual methods. Also, 50 samples showing ABO discrepancies among patients requested for pretransfusion test were selected and compared between two methods. As for samples with ABO discrepancies, further tests such as microscopic examination, reactivity with anti-A1 or ABO genotyping along with medical record review were performed. RESULTS: Agglutination results and grades in healthy adults were consistent between two methods. Meanwhile, 30 (60%) of ABO discrepant samples were related to rouleaux formation and their frequencies and agglutination grades were higher in automated method (Wilcoxon signed rank test, P=0.001). Results of discrepant samples caused by unexpected antibody or ABO subgroup showed no differences between two methods. CONCLUSION: IH-500 automated analyzer was considered useful for mass examination of healthy individuals. Meanwhile, considering the fact that ABO discrepancies by rouleaux formation were more frequent and stronger in automated method, it is recommended to retest their results by manual methods along with medical record review.