Reptilase Clotting Time

Department of Haematology

This test is only performed following discussion with the Consultant Haematologist.

The Reptilase time is useful to confirm or dispute the presence of heparin in a sample.
Where heparin contamination is present the Reptilase time will be normal even though the APTT is prolonged, due to the Reptilase Time's insensitivity to heparin.
Test performed at Oxford Haemophilia centre.

3ml or 3.5ml Trisodium Citrate sample

Coagulation tests must be performed on samples taken by clean venesection and filled to the appropriate level (minimum fill line present on BD bottles).
Overfilled, underfilled and haemolysed samples will give erroneous results and will not be processed.

Two weeks.

Pre analysis storage: do not store, send to laboratory within 2 hours.
Sample retention by lab: Citrate samples are retained for a minimum of 24 hours at 15-30°C. If specialist coagulation tests are requested, one or more aliquots may be frozen until analysis (or up to two months) at between -15 and -40°C. After analysis, these samples will be retained for a further 24 hours at 15-30°C.

This test can be added on to a previous request as long as there is sufficient sample remaining and the sample is less than 4 hours old.

Reptilase Time: 16 - 22 seconds