RBCs, with a diameter of 8 µm, must squeeze through narrow microvascular spaces and endothelial clefts just 1 to 2.5 µm wide. RBC deformability decreases with cellular age and cold storage, but the extent to which splenic clearance selectively removes RBCs with reduced deformability from circulation remains poorly understood. In a murine model, RBCs pooled from seven female mice were…