Test ID: RPTL
Reptilase Time, Plasma
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
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
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
Clot-Based Assay
Measures conversion of fibrinogen to fibrin clot after addition of reptilase.
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
RT (Reptilase Time)
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
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: For single orders, 1 mL. If ordering a profile, refer to specific Coagulation Profile ordered.
Collection Instructions:
1. Spin down, remove plasma, and spin plasma again.
2. Freeze specimen immediately at < or =-40 degrees 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 Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | Mild OK; Gross reject |
| Lipemia | Mild OK; Gross reject |
| Icterus | Mild OK; Gross reject |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Plasma Na Cit | Frozen | 14 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory 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.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
14-23 seconds
Interpretation Provides information to assist in interpretation of the test results
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 |
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The reptilase time test has limited diagnostic value when ordered as a stand-alone test.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
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
Method Description Describes how the test is performed and provides a method-specific reference
The reptilase time assay is performed on the Beckman Coulter 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 405 nm.(Owen CA, Bowie EJW, Thompson JH: Tests of hemostasis and blood coagulation. In The Diagnosis of Bleeding Disorders. Second edition. Boston, MA, Little, Brown and Company, 1975, pp 85-154)
Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.
Monday through Friday
Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
85635
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| RPTL | Reptilase Time, P | 6683-7 |
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