RESUMO
BACKGROUND: RBCs frozen in 40 percent (wt/vol) glycerol are currently approved by the FDA and the AABB for storage at -80 degrees C 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 -80 degrees C 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 4 degrees C. 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 4 degrees C but did correlate with the storage length at 4 degrees C before cryopreservation. CONCLUSION: The data reported in this study demonstrate that RBCs can be stored at -80 degrees C beyond 10 years with acceptable in-vitro quality and suggest that more defined criteria for the cryopreservation process be adopted.
