Factors Affecting Hemagglutinations Strength in ABO Blood Group Typing Test Using the Tube Method

ABSTRACT

BACKGROUND: The ABO blood group typing test (ABO test) is an initial pre-transfusion test based on hemagglutination. Although various factors affect hemagglutination strength, few studies have examined how these factors can be applied in clinical laboratories and their effects on hemagglutination. This study was conducted to analyze the factors affecting hemagglutination strength in the ABO test using a tube method applied in many laboratories. METHODS: We conducted a detailed questionnaire survey of 51 laboratories which use the ABO test with a tube method. We also analyzed the results of the ABO test (cell and serum typing) with 40 specimens using factors affecting hemagglutination at a tube method and applied differently in each laboratory. RESULTS: Each laboratory used various methods to prepare red cell suspensions as specimens or reagents and used different reagent to sample ratios, centrifugation protocols, and shaking test tubes before evaluating hemagglutination strength. By testing various combinations of these factors, direct sampling from the red cell layer of the original specimen was found to have the largest effect on lowering hemagglutination strength in cell typing tests. In serum typing tests, various factors influenced hemagglutination strength, including shaking the tube before analysis and the concentration of a home-made red cell suspension used as a reagent. CONCLUSIONS: To achieve accurate results in the ABO test by the tube method, detailed guidelines that include the factors affecting hemagglutination strength determined in this study should be established.