Effect of glass contact on the clotting time of carp [Cyprinus carpio] blood

Clotting times of carp blood were determined using three kinds of test tubes: glass, silicone treated glass and polystyrene tubes. In order to eliminate the effect of glass contact, test plasma was prepared using tools made of plastic. When determining the recalcification time (RT), clot formation was observed only in the glass tubes and no clot was formed in either the silicone treated glass or the polystyrene tubes. Plasma in contact with glass beads clotted in polystyrene tubes and the clotting time was shortened when the amount of added glass beads was increased. Significant differences were also observed in partial thromboplastin time (PTT) and prothrombin time (PT), while no noticeable differences were observed in activated partial thromboplastin time (APTT). These findings suggest that carp blood has a XII-like factor which is converted to the activated form by contact with glass or ellagic acid.