Red cell concentrates stored in additive solutions have limitations for use in the pediatric population. Our survey of 10 pediatric institutions found that Nutricel supernatant was often removed prior to infusion. Examination of packed red cells showed a potassium concentration in excess of 15 mmol/l by day 7 in AS-3 and 40 mmol/l by day 35. Comparison with cells stored in CP2D and CPDA1 showed that the total mass of potassium was highest in AS-3 (5.6 mmol/l) as was the phosphate. The total mass of citrate and glucose was considerably increased in the AS-3 system at 1.73 mmoles and 3.23 mmoles. All had a pH less than 6.6 at day 35. The high concentration of potassium in AS-3 raises concern for the potential for hyperkalemic dysrhythmias during massive transfusion while the citrate load has clinical implications for divalent cation homeostasis during rapid infusion or exchange; the glucose may induce hyperglycemic sequelae.