A hypotonic storage solution did not prolong the viability of RBCs

BACKGROUND: Hypotonic storage solutions and WBC filtration are both reported to improve RBC viability. This study tested the ability of an investigational hypotonic storage solution (AS-24, Medsep Corp.) to extend the viability of liquid-stored RBCs to 8 weeks. STUDY DESIGN AND METHODS: In a pair of crossover trials, 11 RBC units, WBC-reduced by filtration and stored in AS-24 for 8 weeks, were compared with units from the same donors that were stored for 6 weeks in AS-3, and 13 RBC units, WBC-reduced by filtration and stored in AS-3 for 8 weeks, were compared with units from the same donors that were stored for 6 weeks in AS-3. Viability was measured by the Cr-51/Tc-99m double-isotope method. RESULTS: RBC viability at 8 weeks averaged 64 +/- 3 percent in the AS-24 units and 67 +/- 2 percent in the AS-3 units. It was equal at 77 +/- 3 percent and 77 +/- 2 percent after 6 weeks' storage in AS-3 in both trials. CONCLUSIONS: Prestorage WBC reduction and storage in AS-24 did not extend RBC viability to 8 weeks. The improved viability previously demonstrated with storage of dilute suspensions of RBCs in hypotonic solutions is probably caused by factors other than the hypotonicity.