Reptilase Time

Laboratory assay overview

In patients with prolonged clotting times, this test may help diagnose dysfibrinogenemia or exclude heparin contamination. In heparinized or hemophiliac patients, this test may be used in conjunction with or instead of thrombin time to help diagnose congenital and acquired disorders of fibrinogen [1]. Reptilase is a venom enzyme from Bothrops snakes and has thrombin-like activity. Reptilase time is often used in conjunction with thrombin time to detect anomalies of fibrinogen. These anomalies can be congenital (eg, dysfibrinogenemia, hypofibrinogenemia, afibrinogenemia) or acquired (eg, hypofibrinogenemia as a result from disseminated intravascular coagulation or liver disease). In patients with abnormal clotting times, thrombin time and reptilase time can help screen for dysfibrinogenemia [2]. Because reptilase time is insensitive to thrombin inhibitors (eg, heparin or hirudin), it can be used to determine heparin contamination in patients with prolonged clotting times [1]. A prolonged thrombin time and a normal reptilase time generally indicate heparin contamination. Note that reptilase time may be slightly prolonged in healthy newborns [1]. The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings. References 1. Cunningham MT, et al. Arch Pathol Lab Med. 2002;126(4):499-505. 2. Karapetian H. Methods Mol Biol. 2013;992:273-277.

Laboratory assay overview

This test is used for diagnosis of fibrinogen deficiency, both congenital and acquired, as well as screen for dysfibrinogenemia.6 Normal values for reptilase time when thrombin time is prolonged suggests the presence of heparin or a direct thrombin inhibitor.