A novel protocol for cryopreservation of paediatric red blood cell units allows increased availability of rare blood types

There is a growing concern for shortage in future blood supply, caused by a predicted decrease in eligible blood donors and simultaneous increase in recipients. Cryopreservation of split red blood cell units could increase stock supply by reducing waste of rare blood. This would be particularly useful in paediatric care where very small volumes often are transfused. The aim of this study was to develop a cryopreservation protocol for split units using the closed-system automated cell processor ACP215, as such protocols are currently missing.Using a pool-and-split design, red blood cell units (N = 8) were glycerolized and frozen, either as standard volume reference units, or further divided into three smaller split units each. After thawing/deglycerolization, the supernatant of the smaller splits was reduced by additional centrifugation, and new SAGM was added to 60% haematocrit. The units were analysed for storage lesion effects up to ten days post-thawing.Haemolysis and extracellular potassium ion levels were lower in the split units than in the whole units from day three onwards. The metabolic parameters pH, ATP, glucose and lactate were also lower, though likely caused by lower additive solution pH rather than storage.Split units of red blood cells can be successfully cryopreserved using the ACP215. In addition to favourably low haemolysis and potassium, they also have higher haematocrit than corresponding whole units and enable involvement of fewer donors at repeated transfusions. These characteristics are all desirable features in paediatric care.