Distribution of blood gases, glucose and lactate within stored blood units

The distribution of respiratory gases, hydrogen ions, glucose and lactate were studied in red cells suspended in SAGM solution and stored undisturbed at +4 degrees C in plastic (PVC) bags. After 42 days' storage there were considerable concentration differences between the supernatant and the red cell layer, as well as concentration gradients within the latter. Thus, pO2, sO2, pH and the glucose concentration were higher in the supernatant and pCO2 and the lactate concentration were higher in the red cell layer. These findings show that sampling from the mixed content of blood which has been stored sedimented in plastic containers will not be representative for the erythrocyte environment at the end of shelf life. This is of importance in attempts to understand storage effects on red cells.