Method for the preparation of at least one compound with biological properties from blood, where said method is performed in sealed tubes at a pressure below atmospheric pressure, thereby reducing or preventing the bacterial contamination of the compound through handling. The method comprises the repetition, for as many times as is required, of the following steps: connecting a second container that is vacuum-sealed to an extraction device connected in turn to a first container that contains blood separated into fractions, waiting for a period of time until the required fraction(s) is/are transferred, and removing said second container, with it thus being possible to obtain several second containers with different compounds for different medical applications including biological therapies. The steps may be performed in a closed system, without removing the caps of the containers, or alternatively the first container may be opened prior to the introduction of the extraction device.