Background: Red blood cell (RBC) function is closely associated with patient outcome. The deterioration in RBC function plays a critical role in the impairment of circulation and tissue oxygenation, which may cause an increased risk of postoperative complications and mortality. Objective: To review the risk factors affecting RBC function, the potential clinical consequence thereof, and blood conservation strategies as well. Content: Red blood cells are ideal vehicles of oxygen delivering for their appropriate physical, chemical and molecular properties. Changes to those properties, as occur under various blood banking conditions, during intraoperative cell salvage procedure and after transfusion to patient, may lead to circulatory impairment. Studies that have evaluated the clinical consequences of decreased RBC function are overviewed in this article. Potential solutions that may contribute to RBC function monitoring and optimizing are also discussed. Trend: Make further improvement on understanding RBC function, evaluating clinical consequences of transfusion and reducing adverse events are imperious demanded.