Evaluation of red blood cells stored at-80°C in excess of 10 years

BACKGROUND: RBCs frozen in 40 percent (wt/vol) glycerol are currently approved by the FDA and the AABB for storage at -80degreesC for up to 10 years. STUDY DESIGN AND METHODS: This study examined 20 RBC units that had been cryopreserved in 40 percent (wt/vol) glycerol and stored at -80degreesC for up to 22 years. Measures of the freeze-thaw-wash (FTW) recovery, ATP, 2,3-DPG, methemoglobin, RBC indices, morphology, and osmotic fragility were made immediately after deglycerolization and after 24 hours of storage at 4degreesC. RESULTS: RBCs frozen for longer than 10 years had acceptable mean FTW recovery, normal oxygen transport function, RBC morphology, RBC indices, methemoglobin, and osmotic fragility. Statistical analysis indicated that the in-vitro viability and function of cryopreserved RBCs was not dependent on the length of frozen storage or postthaw storage at 4degreesC but did correlate with the storage length at 4degreesC before cryopreservation. CONCLUSION: The data reported in this study demonstrate that RBCs can be stored at -80degreesC beyond 10 years with acceptable in-vitro quality and suggest that more defined criteria for the cryopreservation process be adopted.