Activity of clotting factors in fresh-frozen plasma during storage at 4°C over 6 days

Fresh-frozen plasma (FFP) requires thawing, which delays availability. We investigated clotting factor activity and bacterial contamination of FFP when stored at 4 degrees C +/- 2 degrees C for 6 days. Plasma of 20 healthy plasma donors was sampled, frozen, and analyzed at baseline and repeatedly over a period of 6 days after thawing. The activity of fibrinogen, Factor (F)II, FV, FVII, FVIII, F IX, FX, XI, FXII, FXIII, antithrombin III (ATIII), von Willebrand factor antigen (VWF-Ag), protein C (PC), and free protein S (FPS) were determined and analyzed over time. Immediately after thawing there was a significant decrease of fibrinogen (-9%), FII (-7%), FV (-14%), FVII (-12%), FX (-11%), FXIII (-20%), PC (-7%), and ATIII (-4%), whereas FVIII (+8%), F IX (+1%), FXI (+11%), FXII (-1%), FPS (-1%), and VWF-Ag (-6%) remained stable without significant change. Over 6 days after thawing fibrinogen, ATIII (+2%) and VWF-Ag (+2%) remained stable whereas FXII (+2%), FXIII (+6%), and PC (+3%) changed significantly over time and increased at the end. FII (-8%), FV (-16%), FVII (-31%), FVIII (-47%), F IX (-12%), FX (-10%), FXI (-25%), and FPS (+/- 0%) changed also significantly over time and decreased at the end. All clotting factors and inhibitors remained within the reference range requested by quality assurance regulations. No FFP bag showed bacterial contamination. This provides evidence for maintaining quality of thawed FFP and may improve rapid availability in emergency situations and reduce cost for health care givers.