A blood washing device is employed for recovering shed blood or other sources of blood and preparing packed red cells therefrom. The device employs a gravity sedimentation procedure but achieves a shortened washing period by using an aggregating reagent for aggregating or agglomerating the red cells so as to increase their sedimentation velocity during the gravity sedimentation. The wash period is further shortened by employing a vessel with a flat shallow configuration for shortening the sedimentation path length of the aggregated red cells. A non-turbulant removal of the resultant broad shallow layer of sedimented red cells is achieved by carefully tilting the vessel after the sedimentation step so as to induce the sedimented red cells to slide or shift into a funnel configuration within the vessel. After the red cells have shifted into a funnel configuration, they are allowed to stand in that configuration so as undergo further concentration. As the red cells become packed, an elutriation of the intercellular fluids occurs. The resultant packed red cells are then carefully drained from the bottom of the funnel configuration for reinfusion into the patient. The period of the wash cycle is sufficiently short that a patient's shed blood can often be recovered during an operation and then washed and reinfused into the same patient during the same operation or shortly thereafter. Autologous transfusions are useful in cases where there is a shortage of blood or where the safety of donor blood is in question.