"Canine transfusion medicine - alloimmunization after transfusion: serial crossmatching study and evaluation of different crossmatching techniques" Transfusion medicine is an important aspect of intensive care and emergency medicine. To prevent potential complications and to maintain the highest possible safety standards during transfusions, guidelines and testing procedures for compatibility testing have been developed. This dissertation describes the performance of crossmatching as part of compatibility testing in dogs. In the first part of this work, serial crossmatch tests were performed using the tube agglutination method, both before and within the first few days directly after a transfusion. The aim was to investigate the point in time at which a reaction, as a possible sign of alloimmunization as a result of a transfusion, was detectable. 16 dogs developed a weakly positive crossmatch test to their original donor's blood within 1 to 13 days (median day 4). Interestingly, a weak positive crossmatch test was detected in 12 dogs within four days after an initial transfusion. This could indicate an early alloimmunization as a result of a transfusion, although non-specific agglutination cannot be ruled out. Despite these findings, we did not observe a transfusion reaction in this part of the study. Nevertheless, as already suspected in several studies, the formation of alloantibodies against blood group antigens with low antigenicity could lead to a shortened life span of the transfused erythrocytes or acute complications in further transfusions. For this reason, it is recommended that crossmatching should be performed before each secondary transfusion as a part of routine compatibility testing when the clinical setting allows it. In the second part, various commercially available crossmatch test kits were compared to the tube agglutination method at different degrees of agglutination for agreement of the results and practicability. In a pilot study, a gel-tube procedure [GR], an antiglobulin-enhanced geltube procedure [AGR], and an immunochromatographic procedure [ICS] were evaluated with 28 different recipient-donor pairs. Compared to the tube agglutination method, the various test kits were easier to perform and were more time-efficient, due to a shortened incubation time. Overall, the evaluation revealed 85.7% agreement of the AGR, 60.7% agreement of the GR, and 35.7% agreement of the ICS method with the tube agglutination method. When focusing solely on macroscopically positive test results, the agreement between the tube agglutination method and the test kits was 100%, 62.5%, and 0%, respectively. The clinical relevance of weakly positive crossmatch tests is still unclear, but the transfusion of incompatible blood products can trigger hemolytic transfusion reactions. Therefore, the gel tube as well as the immunochromatographic procedure had an insufficient sensitivity. Using the antiglobulinenhanced gel-tube method instead, only 4/9 weak positive crossmatch tests, in which only microscopic agglutination with a grade of agglutination of 1+ - 2+ was visible with the tube agglutination method, were determined to be compatible. All other crossmatch test results were concordant with those of the tube agglutination method. Nevertheless, this procedure was significantly less time-consuming compared to the tube agglutination method (median 13,5 minutes less). For this reason, it offers a viable alternative to the laboratory method, especially in emergency situations.weiterlesen