The invention relates to an apparatus (9) for extracting at least one blood component contained in a primary bag (1) of a system of bags, said system of bags further including at least one bag (4) of solution containing an additive solution for said blood component, and at least one satellite bag (3) for collecting said blood compound with said additive solution added thereto, said bags (1, 3, 4) being connected to one another by tubes, said apparatus including: an extraction device (14) for extracting the blood compound by compressing the primary bag (1), a monitoring device (15) for enabling said extracted compound or said combination of the extracted compound and the additive solution to be transferred to the collecting satellite bag (3) via the tubes, an agitation device (16) for agitating the collecting satellite bag (3), and a drive system for controlling said extraction device (14), said monitoring device (15) and the agitation device (16), said system being designed so as to enable the uniform mixing of the extracted blood compound and the additive solution.
