Reptilase Time, Plasma RT (Reptilase Time)
Evaluation of a prolonged thrombin time (TT): It is mainly used to confirm or exclude the presence of heparin in the specimen or specimen type
Evaluating hypofibrinogenemia or dysfibrinogenemia in conjunction with the TT and fibrinogen assay
1. Spin down, remove plasma, and spin plasma again. 2. Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C, or ideally < or =-40 degrees C.
Additional Information: 1. Double-centrifuged specimen is critical for accurate results as platelet contamination may cause spurious results. 2. Each coagulation assay requested should have its own vial.
The reptilase time test has limited diagnostic value when ordered as a stand-alone test.
Prolonged clotting times may be associated with a wide variety of coagulation abnormalities including: -Deficiency or functional abnormality (congenital or acquired) of any of the coagulation proteins -Deficiency or functional abnormality of platelets -Specific factor inhibitors -Acute disseminated intravascular coagulation -Exogenous anticoagulants (eg, heparin, warfarin)
The prothrombin time (PT) and activated partial thromboplastin time (APTT) are first-order tests for coagulation abnormalities and are prolonged in many bleeding disorders. A battery of coagulation tests is often required to determine the cause of prolonged clotting times. The thrombin time (TT) test is used to identify the cause of prolonged APTT or dilute Russell's viper venom time (DRVVT). Reptilase time (RT) test is used to evaluate a prolonged TT.
Reptilase is a thrombin-like enzyme isolated from the venom of Bothrops atrox. Thrombin splits small fibrinopeptides A and B from fibrinogen molecules, producing fibrin monomer, which polymerizes to form a clot. Reptilase, however, splits off fibrinopeptide A but not B, which results in fibrin polymerization. In contrast to thrombin and the TT test which are inhibited by heparin, the RT is normal in the presence of heparin. Similar to the TT test, the RT is prolonged in the presence of hypofibrinogenemia and dysfibrinogenemia.