Abnormality of coagulation Prolonged reptilase time 2019-09-05T13:57:09Z Reptilase time may be increased with a deficiency of fibronogen. Unlike the thrombin time, this assay is not affected by the presence of heparin, hirudin, or direct thrombin inhibitors in a blood sample. An abnormally increased duration of the reptilase time. Reptilase time is a functional plasma clotting assay, which is based on the enzymatic activity of batroxobin. By specifically cleaving fibrinogen A from fibrinogen, batroxobin leads to the formation of a stable fibrin clot. The time, starting from the addition of batroxobin to the plasma sample, until clot formation is the reptilase time and is given in seconds.