Thrombin generation and coagulation factor content of thawed plasma and platelet concentrates.

BACKGROUND: We assessed the haemostatic capacity of thawed plasma produced after ambient storage of whole blood for 24 h (RTFP24), and the supernatant of buffy-coat derived platelet concentrates (PC).

METHODS: Platelet concentrates (n = 20) were tested on days 1, 5 and 7 of storage at 22°C and RTFP24 (n = 10) immediately following thawing and after 4 and 6 days storage at 4°C. Coagulation factor activity, thrombin generation ± an activator of protein C (PROTAC) and rotational thromboelastometry (ROTEM) were assessed.

RESULTS: In plasma and buffy-coat derived PC, there was a < 10% loss of factors II, IX and FX, but much higher loss of factors FV, FVII and FVIII. In plasma, the total or peak amount of thrombin generated was unaffected by storage for 6 days, with or without Protac, but there was an increase in lag time and decreased rate of clot formation by ROTEM. In PC, but not plasma, there was a 16% increase in FXII activity and increase in resistance to activated protein C, co-incidental to 30% loss of free protein S.

CONCLUSIONS: These data suggest thrombin generation is relatively unaltered when RTFP24 is thawed and stored for 6 days, and that the supernatant of PC has significant haemostatic capacity.