Transfusion blood compatibility evaluation in cats using Crossmatch tests

Crossmatch tests are used for rapid identification of natural or induced anti-erythrocyte antibodies (hemolizines and hemaglutinines), reducing the risk of transfusion reactions. This test is recommended for every feline patient with unknown history and is mandatory starting with the second transfusion even if the blood used is of the same blood group or comes from the same donor. The purpose of this study is to appreciate the efficacy of some Crossmatch tests that evaluate transfusion compatibility in cats, by: comparing different Crossmatch tests and some anticoagulants; identifying donor and patient carriers of anti-erythrocyte antibodies; implementing a rapid Crossmatch test on slides and compatibility evaluation in cancer patients. Using one original and five known Crossmatch techniques on slides, pre-transfusion compatibility was tested on four sample groups of blood: 1- blood drawn on EDTA or CPDA1 for recipient (n=7) -donor (n=7) pre-transfusion compatibility evaluation; 2- blood drawn on EDTA or CPDA1 from healthy donors (n=30) and recipients (n=30); 3- blood samples drawn on EDTA (n=10) and CPDA1 (n=10) for evaluating their influence on agglutination reactions in stored blood (at 2-8oC for up to 15 days); 4- canine (n=5) and feline (n=5) blood samples to serve as “positive control reactions”. The negative Crossmatch test results in group one led to whole blood (WB) transfusions in all seven patients, from which we have found only one patient with agglutination reactions, indicating incompatibility with one of the donors. Test results from group two revealed a large number of agglutination reactions (eight for major and seven for minor Crossmatch), despite the fact that none of the subjects were previously transfused. Washing the red blood cells helped diminish the number of rouleaux for these patients, but without reducing the number of agglutinations. In group 3 we have not observed agglutination reactions after three-day storage in the blood samples drawn on EDTA, where as the samples drawn on CPDA1 maintained this capacity even after fifteen days of storage, with rouleaux formation being less frequent. The interspecies agglutination reactions in group four were at maximum intensity that we used as “positive control”. Crossmatch tests on slides proved to be as relevant as the ones performed in tubes for the detection of high titers of allo-antibodies, uncertain reactions needing to be clarified by adding normal saline and/or further examination under a microscope. Agglutinations can be attributed to group allo-antibodies or some unknown erythrocyte antigens.