Reptilase Clotting Time

Department of Haematology

Notes

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.

Sample Requirements

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.

Turnaround Time

Two weeks.

Sample Storage and Retention

• 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.

Reference Ranges

Reptilase Time: 13.7 - 17 seconds