An apparatus for extracting at least one blood component contained in a primary bag of a system of bags, said system of bags comprising at least one bag of solution containing an additive solution for said blood component and at least one collecting satellite bag configured to collect said blood component to which said additive solution has been added, said bags being connected to one another by tubes, said apparatus comprising an extraction device configured to extract the blood component by compressing the primary bag, and a control device configured to transfer said extracted component or of said extracted component and of the additive solution, to the collecting satellite bag by the intermediary of tubes, further comprising: an agitation device, and a drive system, said system being designed to enable the uniform mixing of the extracted blood component and of the additive solution in said collecting satellite bag.