Stability of human thrombin produced from 11 ml of plasma using the thrombin processing device.

Autologous thrombin can be produced by activating the patient's own plasma. By adding calcium chloride (CaCl2) to the anticoagulated plasma, the coagulation cascade will be initiated, and active thrombin will be produced. However, thrombin obtained by this method degrades very quickly and is not practical for use during surgery. The aim of this study was to investigate the stability of the thrombin produced using the thrombin processing device (TPD; Thermogenesis Corporation). The TPD consists of a tubular chamber containing a negatively charged surface for activation. Plasma (11 ml) and reagent (CaCl2 and ethanol, 3.75 ml) were added to the TPD, and active thrombin was harvested after a 20-minute incubation. The production of thrombin was done at 18 degrees C (64 degrees F), 24 degrees C (75 degrees F), and 27 degrees C (81 degrees F) (n = 4/group). The produced thrombin was stored at the production temperature, 4 degrees C (39 degrees F), and 35 degrees C (95 degrees F). The thrombin activity was assessed by time to clot formation, using a fibrinogen concentrate as substrate, after 2, 4, and 6 hours of storage. Thrombin produced at 18 degrees C had clot times of less than 5 seconds for 2 hours (4.42 +/- 1.3 seconds) when stored at 4 degrees C, but 4 hours (4.1 +/- 1.3 seconds) when stored at 35 degrees C. In contrast, when thrombin was produced at 24 degrees C, the clot times were 4.3 +/- 0.7 and 4.6 +/- 1.6 seconds at 4 degrees C and 35 degrees C, respectively, for up to 6 hours. Similar results were obtained for thrombin produced at 27 degrees C. Active thrombin produced by the TPD is dependent on both the production temperature and the storage temperature. Autologous human thrombin with a stability of up to 6 hours can be obtained using the TPD when produced at 24 degrees C or 27 degrees C and stored at 4 degrees C.