A blood bag system includes a BC pooling bag for centrifugation of a buffy coat, a filter for removing white blood cells from a supernatant liquid transferred from the BC pooling bag, a platelet preserving bag for reserving the supernatant liquid that has passed through the filter, a first tube connecting the BC pooling bag and an inlet of the filter, a second tube connecting the platelet preserving bag and an outlet of the filter, and a cassette to be fixed in the centrifugation and separation apparatus. The first tube and the second tube are disposed within the cassette. The cassette includes a first clamp section for closing and opening the first tube, and a second clamp section for closing and opening the second tube.

A blood bag system includes one clamp. The clamp includes a base formed with an insertion hole through which a second tube and a third tube are inserted. A first slit for pressing the outer circumferential surface of the second tube inward such that a second flow channel is closed, and a second slit for pressing the outer circumferential surface of the third tube inward such that a third flow channel is closed, are provided in a wall section forming the insertion hole.

An improved method for separating whole blood into components and collecting a desired blood component. The method allows a desired blood component to be subjected to centrifugal forces within a separator for prolonged periods of time, yielding a cleaner cut and higher yield of the desired blood component. Whole blood is drawn from a source and pumped into a separator, the undesired blood components are removed from the separator at rates so as to build up the desired blood component in the separator. The desired blood component is only removed after a predetermined amount of the desired blood component has built up in the separator. It is preferred that the desired blood component be buffy coat and that the method be used to perform photopheresis treatments. In another aspect, the invention is a method of performing a full photopheresis treatment to treat diseases in a reduced time, preferably less than about 70 minutes, and more preferably less than about 45 minutes.

An improved method for separating whole blood into components and collecting a desired blood component. The method allows a desired blood component to be subjected to centrifugal forces within a separator for prolonged periods of time, yielding a cleaner cut and higher yield of the desired blood component. Whole blood is drawn from a source and pumped into a separator, the undesired blood components are removed from the separator at rates so as to build up the desired blood component in the separator. The desired blood component is only removed after a predetermined amount of the desired blood component has built up in the separator. It is preferred that the desired blood component be buffy coat and that the method be used to perform photopheresis treatments. In another aspect, the invention is a method of performing a full photopheresis treatment to treat diseases in a reduced time, preferably less than about 70 minutes, and more preferably less than about 45 minutes.

A blood bag system includes a BC pooling bag for centrifugation of a buffy coat, a filter for removing white blood cells from a supernatant liquid transferred from the BC pooling bag, a platelet preserving bag for reserving the supernatant liquid that has passed through the filter, a first tube connecting the BC pooling bag and an inlet of the filter, a second tube connecting the platelet preserving bag and an outlet of the filter, and a cassette to be fixed in the centrifugation and separation apparatus. The first tube and the second tube are disposed within the cassette. The cassette includes a first clamp section for closing and opening the first tube, and a second clamp section for closing and opening the second tube.

A blood bag system is equipped with a blood collection bag in which blood is accommodated, a parent bag and a child bag in which blood components separated from the blood are accommodated, and flow paths that connect the blood collection bag and the parent bag. The blood collection bag, the parent bag, the child bag, and the flow paths are formed integrally by a first sheet body and a second sheet body that is superimposed on the first sheet body, and meandering sections which are repeatedly folded back on themselves are provided in the flow paths.