In accordance with the requirements of ISO 10993-4, we established the feasibility of conditions for animal blood application in vitro to identify substances that induce thrombus formation and confirmed the differences in blood reactivity between animals necessary for interpreting in vivo results in this study. To this end, differences in the response of rabbit, pig, and monkey blood to each anticoagulant presented in ASTM F2888-19 were tested.

It was confirmed that the direct heparinization method had a higher test sensitivity than that of recalcified sodium citrate, thus distinguishing thrombotic substances regardless of the test species. Particularly in pig blood, platelet and white blood cell counts showed the greatest decrease after reactions with various test materials.

Expression of β-TG and PMN-elastase, indicators for platelet and leukocyte activities, was confirmed in pig blood when reacted with various test materials. A decrease in platelet count and significant increase in β-TG were observed in the black rubber test group, which was the positive candidate material. Conversely, a decreased leukocyte count was confirmed, but an increase in the expression of PMN-elastase was not observed. This result satisfied the ISO 10993-4 criteria for determining a positive thromboembolic substance.

This study provided additional information on the selection of anticoagulants for the design of trials and selection of animal species for evaluating thrombosis formation on medical device materials by using the methods described in ISO 10993-4 and ASTM F2888-19.