Clinical relevance
In the presence of a predetermined quantity of Reptilase, normal plasma will clot in a finite and constant time. The Reptilase time is not affected by Heparin and can therefore be used when investigating prolonged APTT results where Heparin contamination is a possibility.
A prolonged Reptilase time can indicate anomalies of fibrinogen such as dysfibrinoginaemia, hypofibrinogenaemia (as seen in DIC and liver disease) and afibrinogenaemia. Reptilase can also be prolonged in the presence of abnormal Antithrombins such as those which can appear in myeloma.
Reference range
Current laboratory (adult, M/F) normal ranges are as follows:
- 15.7 – 20.2 seconds
Minimum volume
The volume of blood in coagulation samples must lie within the volume range as indicated by the size of the black fill arrow present on tubes. Volumes above or below the arrow will result in sample rejection to ensure validity of results.
Turnaround time
- Urgent: 1 hour
- Routine: 4 hours
Age of sample
Samples will be rejected if received more than 8 hours after venepuncture.
Specimen requirements
- 1 blue top (sodium citrate) sample.
- All coagulation tubes must be adequately filled (see above).
- All coagulation tubes must be mixed several times by gentle inversion immediately after venepuncture. Mixing the sample with the anticoagulant stops the sample clotting within the tube.
Limitations
- It is not possible to provide results on haemolysed, or lipaemic samples. These will be rejected with the appropriate comment.
- Sample tubes that have expired cannot be accepted.
Analysing laboratory
- Coagulation Lab, James Cook University Hospital, Marton Road, TS4 3BW
- Coagulation Lab, Friarage Hospital, Northallerton, DL6 1JG