An additive solution for the storage of red blood cells was evaluated for use in dogs. Blood collected from 6 dogs was processed into packed red blood cells and stored for 35 days in the additive solution Nutricel (Miles, Inc, Pharmaceutical Division, West Haven, CT). Packed red blood cells stored in citrate-phosphate-dextrose-adenine (CPDA-1; Fenwal Laboratories, Baxter Health Care Corp, Deerfield, IL) also were evaluated for comparison. Red blood cell 2,3-diphosphoglycerate (2,3-DPG) concentration, adenosine triphosphate (ATP) concentration, percentage hemolysis, and pH were determined. The red blood cell post-transfusion viability (PTV) after 35 days of storage was assessed with both single-labeled chromium 51 (5'Cr) and double-labeled technetium 99m/chromium 51 (99"T~/5'Cr) techniques. Mean ATP concentration and percentage hemolysis of the cells stored in Nutricel were 1.1 pmol/g hemoglobin (Hb) and 0.28% respectively and did not differ significantly (P < .05) from the he use of packed red blood cells from dogs for transfu-