Reptilase-R--a new reagent in blood coagulation.

Abstract

Summary. Reptilase®‐R, a purified thrombin‐like snake‐venom enzyme from Bothrops atrox, has been tested for its usefulness as a substitute for thrombin in two coagulation assay systems. Reptilase was found to be more stable than thrombin and not to be inhibited by heparin and hirudin.Performance of the Reptilase time allows the rapid exclusion of heparin contamination in plasma samples with prolonged thrombin times. In the presence of fibrinogen/fibrin split products, the Reptilase time is less prolonged than the thrombin time, whereas in patients with prolonged thrombin times because of congenital dysfibrinogenaemia the inverse is found. Thus, performance of both Reptilase time and thrombin time allows the rapid identification of three major causes for a prolongation of the thrombin time. In patients on heparin therapy because of a defibrination syndrome, the Reptilase time may replace the thrombin time as a guide for the degree of coagulation inhibition by FDP, although our results show that it is somewhat less sensitive.Reptilase can also be substituted for thrombin in the rapid chronometric fibrinogen assay. Unfortunately the advantages of reagent stability and insensitivity to heparin are balanced by a lesser reproducibility, especially in the presence of FDP.