Reptilase time
- Description
- The reptilase time reagent is added directly to test plasma and the time to clot is recorded. It contains a fraction of the venom of the Lancehead snake (Bothrops atrox) which is a snake venom thrombin-like enzyme (SVTLE) that cleaves fibrinopeptide A but not fibrinopeptide B from fibrinogen to form fibrils of fibrin I. Heparin elevates APTT and thrombin time because it potentiates antithrombin but the reptile enzyme is unaffected by even a potentiated human inhibitor and will generate a normal clotting time in the presence of heparin. Abnormalities of fibrinogen will generate elevated reptilase times.
- Clinical details
- Blood samples taken from heparinised lines are occasionally contaminated with heparin and can falsely elevate APTT, thrombin time and even prothrombin time. To exclude heparin contamination, a reptilase time is performed because it is insensitive to heparin.
- Related condition
- Reference range
0.95 - 1.07
- Units
- Ratio
- Testing site
- Synnovis : Blood Sciences : St Thomas' Hospital
- Laboratory
- Diagnostic Haemostasis and Thrombosis
- Sample type and volume required
- External requests: Citrated platelet poor plasma 400µL x 1 aliquot Internal requests: please refer to EPR label
- Special sample instructions
The sample should be analysed within 4 hours of venepuncture. Please ensure sample tubes are filled exactly to the fill-line as underfilling creates a dilution error and leads to inaccurate results.
- Turnaround time
- 4 hours
- Contacts
Diagnostic Haemostasis and Thrombosis Department
St Thomas’ Hospital
Phone: 020 7188 2797
St Thomas’ Hospital
North Wing – 4th and 5th Floors
Westminster Bridge Road
London SE1 7EHGuy’s Hospital
Phone: 020 7188 7188 ext. 53860
Guy’s Hospital
Southwark Wing – 4th Floor
Great Maze Pond
London SE1 9RT
Outside core hours, contact Duty Haemostasis Biomedical Scientist