Coagulation factor activity in platelet concentrates stored up to 7 days: an in vitro and in vivo study

The in vitro and in vivo recovery of coagulation factor activity in platelet concentrates stored up to 172 h was studied. In vitro studies revealed that fibrinogen and antithrombin III levels do not change with storage. Factors II, V, VII, VIII, IX, X and XI all showed statistically significant falls from baseline over the 172 h storage period. However, most factor activities remained above 70%, with the major exception of factors V and VIII. These factors fell to less than 30% activity over the storage period, consistent with their known lability during whole blood storage. In vivo studies after platelet concentrate infusion in patients with concurrent thrombocytopenia and coagulation deficiencies revealed that the measured in vitro activity was recoverable in vivo. We conclude that platelet concentrates stored for 172 h are an adequate source of clotting factors. However, like stored whole blood, they may not provide therapeutic doses of factors V and VIII.