The proposed invention relates to a system for preparing serum or plasma from a blood sample, comprising a main unit (1), comprisingo a sampling chamber (10) for receiving a blood sample, ando a filtration chamber (20) for filtering the blood sample, the filtration chamber comprising a first compartment (21) in fluid communication with the sampling chamber, a second compartment (23), and a filter (22) interposed between the first and second compartments,characterized in that it further comprises a plurality of vials, each comprising a connector, and the main unit comprises a plurality of connectors (30) adapted to cooperate with the vial connectors to achieve a leak-tight communication between the main unit and the vials,and in that the filtration chamber is designed to allow blood filtration by gravity when the main unit is in a position of use.
