Apparatus for extracting one or more components from a composite liquid, namely blood or buffy coat or bone marrow or umbilical cord blood, comprising an aqueous component, namely plasma or an anticoagulant solution or a storage solution for blood cells, and one or more cellular components, namely platelets, white blood cells or red blood cells or stem cells; Apparatus for extracting stem cells from bone marrow; Apparatus for extracting plasma, platelets, white blood cells or red blood cells from blood or a blood fraction; Blood washing apparatus; Centrifuge for the separation of an aqueous component, namely plasma or an anticoagulant solution or a storage solution for blood cells, and one or more cellular components, namely platelets or white blood cells or red blood cells or stem cells, from a composite liquid, namely blood or buffy coat or bone marrow or umbilical cord blood; centrifuge for the separation of plasma, platelets, white blood cells or red blood cells from blood or a blood fraction; Accessories for use with such apparatuses and centrifuges, namely-- filter for filtering a composite liquid, namely blood or buffy coat, or a component of said composite liquid; filter for filtering blood or a blood product; Filter for removing white blood cells from blood or a blood product; collection bag for receiving blood from a donor; separation bag for containing a composite liquid, namely blood or buffy coat or bone marrow or umbilical cord blood, comprising an aqueous component, namely plasma or an anticoagulant solution or a storage solution for blood cells, and one or more cellular components, namely platelets or white blood cells or red blood cells or stem cells, to be separated; circular separation bag for a composite liquid, namely blood or buffy coat or bone marrow or umbilical cord blood; blood product bag for containing plasma, platelets, white blood cells or red blood cells; separation set comprising a separation bag for containing a composite liquid, namely blood or buffy coat or bone marrow or umbilical cord blood; connected to one or more bags for containing one or more components to be extracted from said composite liquid; bag for containing an additive solution for platelets; bag for containing an anti-coagulant solution; Bag for containing a storage solution for red blood cells or white blood cells; blood tubing set comprising blood tubing lines, blood bags, blood access needles and solution bags