Effect of storage time on red blood cell membrane permeability to creatinine and uric acid.

Although there is considerable evidence that blood storage affects red blood cell viability, deformability, and geometry, available data on the effect of blood storage on solute transport across the red blood cell membrane are highly limited. The authors used a stirred ultrafiltration device, with direct cell-free fluid sampling through a semipermeable ultrafiltration membrane, to obtain accurate data on red blood cell membrane permeability to both creatinine and uric acid. Results for influx and efflux experiments can be adequately explained by a passive transport mechanism. The red blood cell membrane permeability to uric acid increased substantially during storage, whereas trends in creatinine permeability were less clear and suggested possible differences between solute efflux and influx experiments. These results provide important insights into the physical and biochemical changes that occur in the red blood cell membrane during storage and also have important implications for analyses of solute removal in hemodialysis.