Blood banks can prepare fibrin sealant by several methods. Allogeneic components allow for banking of the fibrinogen concentrate for immediate use. Autologous components eliminate the risk of transfusion-transmitted disease to the recipient, but not necessarily to the preparer. Ethanol and ammonium sulfate precipitation of fibrinogen concentrate allow use of autologous blood and fast preparation (less than 90 minutes). Cryoprecipitation from liquid plasma is adequate, conserving fresh frozen plasma. Cryoprecipitation by the "freeze-thaw" method has been reported to have the highest fibrinogen yield (7840 mg/dL +/- 1800 mg/dL), whereas ammonium sulfate precipitation has been reported to have the highest bonding strength (41 g/cm2 10 minutes after thrombin addition). Cost, storage, preparation time, and transfusion-transmitted disease all play a role in choice of method.