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Test Code RPTL Reptilase Time, Plasma

Reporting Name

Reptilase Time, P

Useful For

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

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Plasma Na Cit


Specimen Required


See Coagulation Studies in Special Instructions.

 

Specimen Type: Platelet-poor plasma

Collection Container/Tube: Light-blue top (citrate)

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Spin down, remove plasma, and spin plasma again.

2. Freeze specimen immediately at ≤-40° C, if possible.

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.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Plasma Na Cit Frozen 14 days

Special Instructions

Reference Values

14-23 seconds

Day(s) and Time(s) Performed

Monday through Friday

Test Classification

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 U.S. Food and Drug Administration.

CPT Code Information

85635

LOINC Code Information

Test ID Test Order Name Order LOINC Value
RPTL Reptilase Time, P 6683-7

 

Result ID Test Result Name Result LOINC Value
RPTL Reptilase Time, P 6683-7

Clinical Information

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.

Interpretation

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

 

Clinical Reference

1. Greaves M, Preston FE: Approach to the bleeding patient. In Hemostasis and Thrombosis: Basic Principles and Clinical Practice. Fourth edition. Edited by RW Colman, J Hirsh, VJ Marder, et al: Philadelphia, JB Lippincott Company, 2001, pp 783-837

2. Funk C, Gmur J, Herold R, Straub PW: Reptilase-R: A new reagent in blood coagulation. Br J Haematol 1971 July;21(1):43-52

3. Latallo ZS, Teisseyre E: Evaluation of reptilase R and thrombin clotting time in the presence of fibrinogen degradation products and heparin. Scand J Haematol Suppl 1971;13:261-266

Analytic Time

1 hour

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross reject

Other

NA

 

Method Name

Clot-Based Assay
Measures conversion of fibrinogen to fibrin clot after addition of reptilase.