Pilot study on frozen RBC
In this pilot study to test the safety of cryopreserved deglycerolized red blood cells (RBCs), they also found that the red blood cells kept their oxygen carrying function better after being frozen as compared to refrigerated. Just like your vegetables, RBCs wither in room temperature surroundings. This is slowed by cooling them. But they still wither. During a RBC pack’s end of life, it has significantly decreased oxygen carrying capacity compared to a fresh bag of RBCs. The cryopreserved RBCs didn’t lose their oxygen carrying capacity. And when frozen, these RBC packs are approved by the FDA for storage up to 10 years, compared to 30 days for a standard, cooled pack of packed RBCs.
The problem has been to freeze and thaw red blood cells without destroying them. This was solved already in the 1950’s by a method where they added glycerol and was able to keep blood frozen at -70 degrees Celsius. But thawing the blood and removing the glycerol was a meticulous process and you had to use the blood straight away. Modern techniques have automated the thawing and washing, and also lets you keep the blood at 4 degrees Celsius for up to 14 days after thawing.
Future multi-center trial
This pilot study found cryopreserved blood to be safe in healthy adults, and they’re starting a multi center trial to see if cryopreserved blood actually offers advantages like increased oxygen carrying capacity for the receiving patient, as well as longer shelf life. It could change the way we store and use blood.