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
Optical Clot-Based
Reptilase Time, Plasma
RT (Reptilase Time)
Plasma Na Cit
Specimen Type: Platelet-poor plasma
Collection Container/Tube: Light-blue top (citrate)
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. For complete instruction, see Coagulation Guidelines for Specimen Handling and Processing.
2. Centrifuge, remove plasma, and centrifuge plasma again.
3. Freeze plasma immediately (no longer than 4 hours after collection) at -20 degrees C or, ideally below -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.
If not ordering electronically, complete, print, and send a Coagulation Test Request (T753) with the specimen.
0.5 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | Reject |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Plasma Na Cit | Frozen | 14 days |
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
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 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.
14.0-23.9 seconds
As seen in the following table, reptilase time can help distinguish among the various causes of a prolonged thrombin time (TT).
Thrombin Time | Reptilase Time | Causes | Remarks |
Prolonged | Prolonged | Hypo- or afibrinogenemia | Ascertain by determination of fibrinogen |
Prolonged | Prolonged | Dysfibrinogenemia | Ascertain by specific assay |
Prolonged | Normal | Heparin or inhibitor of thrombin | Differentiate by human TT and/or heparin assays |
Prolonged | Prolonged | Fibrin(ogen) split products (FSP) | Ascertain by FSP or D-dimer assay |
The reptilase time test has limited diagnostic value when ordered as a stand-alone test.
Favaloro EJ, Lippi G, eds. Hemostasis and Thrombosis: Methods and Protocols. 1st ed. Humana Press; 2017
The reptilase time assay is performed on the Instrumentation Laboratories ACL TOP. Patient plasma is combined with a reptilase reagent containing a thrombin-like enzyme triggering the coagulation process in the mixture. Time to clot formation is measured optically using a wavelength of 671 nm.(Owen CA, Bowie EJW, Thompson JH. Tests of hemostasis and blood coagulation. In: The Diagnosis of Bleeding Disorders. 2nd ed. Little, Brown and Company; 1975:85-154)
Monday through Friday
This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.
85635
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
RTSC | Reptilase Time, P | 6683-7 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
RTSC | Reptilase Time, P | 6683-7 |