Concentrated Antihemophilic Factor (AHF) from Outdated Blood

The antihemophilic factor (AHF) content of bank blood decreases during storage under standard blood bank conditions. In the present study, an average of 58 per cent of the original activity was present after the usual shelf life of 21 days expired. This material was concentrated by a modification of the Pool cryoprecipitation method. Almost 60 per cent of the residual AHF in the outdated plasma was found in the precipitate. The resulting precipitate was resuspended in about 25 ml of the residual plasma. On a volume basis, this had an average of about four times the activity of fresh human plasma. The cold insoluble material resuspended in residual plasma can be used for therapy without further processing. Following intravenous injection into hemophilic patients, high levels of circulating AHF, in excess of 60 per cent of normal, have been achieved without causing circulatory overload.