RBC deformability and clinical relevance in transfusion recipients.

Red blood cell (RBC) deformability-the ability of RBCs to change shape-is crucial for their passage through microvessels and effective oxygen delivery. Deformability depends on the cell's surface area-to-volume ratio, internal viscosity, and membrane elasticity. Deformability is assessed using single-cell methods like micropipette aspiration and bulk flow techniques such as ektacytometry. RBC deformability decreases during cold storage due to biochemical and structural changes known as storage lesions. Additional processes like cryopreservation and irradiation further impair the deformability of stored RBCs. Donor factors, including age, sex, lifestyle, and health, also influence RBC mechanical properties, affecting transfusion outcomes. Clinically, transfusing RBCs with reduced deformability is linked to impaired microvascular flow, decreased oxygen delivery, and faster clearance from the circulation, especially in patients with chronic or inflammatory conditions. Despite its importance, deformability testing is not yet standard in transfusion practice. New technologies offer potential for routine deformability assessment which could improve transfusion outcomes by optimizing RBC quality and matching units to patient needs.